Howler

You need LOS to detonate the IED regardless of type.  You also need LOS for activation of Radio IEDs.
The triggerman needs LOS and has to be within proper range of the device (the three device types have different ranges).  The triggerman can't be "panicked".  If the triggerman is suppressed to the extent that his LOS, to the device, is broken (fetal position behind a low wall) he will not be able to detonate.  
If the triggerman cannot activate the IED the Target command won't be available.  If the IED is a dud then instead of showing Medium Radio IED (Activated) it will show Medium Radio IED (Malfunction).
An IED can be activated and detonated by any triggerman.  Example: A Wire triggerman can activate and/or detonate a cell or radio IED.
Some vehicles carry radio/cell IED jammers so you can't send a signal to your bomb to explode as it passes. Only wire IEDs work on those vehicles.  Bradleys & Strykers don’t have ECM jammers.  Some UK vehicles have the ECM jammer (don't remember which ones).
And just because I have these screenshots in my Imgur account.    Small, medium, large & huge.  Wire, cell or radio.  

 
And don't forget VBIEDs

Thing is no one needs to buy that concept as that's not how it works in CM. But somehow you seem to keep thinking it does even after AKD explained how it does works.
There are some quirks sometimes with sharing and Syrians have some limited capabilities IIRC, but for me too it does work in all CMx2 games.

None of those other units have thermal weapon sights.  They all have NVGs.
Read my post above again regarding information sharing.
 
It has a thermal weapon sight for the M249.
Yes, it has a much more powerful thermal imager than the weapon sights carried in the rifle squad.
The squad as a whole will be better because it is observing with 3x thermal sights instead of just one.
I think your conceptual problem here is that the thermal weapon sights are tied to the individual weapons and are not shown in the special equipment panel, whereas NVGs (light intensification, not thermal) are shown.  That's why I said the issue was obscure, because it is not readily apparent and takes careful testing to understand.  Possibly we could address this via a mod by denoting the thermal capability on the weapon icon itself?
 

First, the misunderstandings about how spotting works:
When a unit shares a positive contact, it generates a possible contact marker for units in C2 or proximity (including tanks) following a variable amount of time, regardless of whether or not the receiving unit has any chance of spotting the target itself (i.e. a unit in comms / proximity but with LoS completely blocked will still gain the possible contact marker).  If the unit has LoS to the location and has the means to see the given contact under the current conditions, this possible contact marker will increase the chances of the receiving unit gaining a positive contact for itself.  But this is most important: the unit must still spot the contact itself with its own sensors. All spotting has a highly variable "human factor" applied that can lead to significantly different outcomes in the same circumstances.  Anecdotes comparing times to spot are useless for drawing comparative conclusions about spotting beyond possible / not possible.  I don't care if 3 times in a row X spotted Z one minute sooner than Y, that does not mean X is better at spotting Z than Y.  Now repeat this 100 times carefully controlling all other factors and perhaps we can talk about quantitative differences in spotting ability. (Does this suck? Why yes, from experience it really does.) Second, what Erwin is encountering in George's scenario:
The US Mech Inf squad has access to 3x thermal small arms sights: 1 on each M249 and 1 on the Marksman's rifle.  A split off scout team from a full squad includes one M249 gunner, so it too has a thermal optic.  Here is what's a bit weird: the model switch showing these actually on the weapons is tied to a hard day / night time that does not vary based on conditions, but the thermal optics are still considered to be in use when they provide an advantage over day optics.  In this case, they seem to be allowing units with thermal optics to see further into the morning haze. Of the infantry units discussed in the scenario, only units with Javelin CLUs also have access to thermal optics. The units without thermals lose LoS at 1668m (at scenario start on my test map using the same date, time and conditions as George MC's map), so if a unit with thermals has shared a possible contact beyond this range with a unit without thermals, it will remain a possible contact for the receiving unit with no chance of becoming a positive contact unless conditions change or the unit alters its spotting equation (moves, acquires a new sensor). 

Checking Spielberger, the later PzIVs all have 50mm of turret face armor, inclined at 80 degrees. The mantlet (called "roller mount") is also 50mm, curved.
As can be seen on the US Army's 37mm penetration tables, this puts the PzIV at risk of turret penetration somewhat beyond 500m.

Ok, I understand where you're coming from. Of course my intention was never to break anything - I was just explaining the point I made about foxholes above.

Exactly, I need to get reacquainted with CMBN as the last time BFC "improved" unit behavior - I needed to play SF/SF2/BS and avoided BN for near three years...
It's been good to see units surrender and not run back and forth in disarray towards known enemy positions.
Allow me to enjoy this before we break something else... is all I'm saying. No offense intended.

Exactly, I need to get reacquainted with CMBN as the last time BFC "improved" unit behavior - I needed to play SF/SF2/BS and avoided BN for near three years...
It's been good to see units surrender and not run back and forth in disarray towards known enemy positions.
Allow me to enjoy this before we break something else... is all I'm saying. No offense intended.

There are two modes in game: 1) Realtime where you can issue orders every second to your hearts content; and 2) Turn based (WEGO) where you trust the TacAI in 60 second cycles.
The issue seems to be that the TacAI is not behaving as *you* want it to. Personally, I'd be careful what we wished for given the result of  CMBN  v4.00-4.02.
Let's get reacquainted with CMBN before we try to break it again. Please.

Exactly, I need to get reacquainted with CMBN as the last time BFC "improved" unit behavior - I needed to play SF/SF2/BS and avoided BN for near three years...
It's been good to see units surrender and not run back and forth in disarray towards known enemy positions.
Allow me to enjoy this before we break something else... is all I'm saying. No offense intended.

There are two modes in game: 1) Realtime where you can issue orders every second to your hearts content; and 2) Turn based (WEGO) where you trust the TacAI in 60 second cycles.
The issue seems to be that the TacAI is not behaving as *you* want it to. Personally, I'd be careful what we wished for given the result of  CMBN  v4.00-4.02.
Let's get reacquainted with CMBN before we try to break it again. Please.

I can now run Quake 3 on my Raspberry Pi Model 4 (RPI4) using Vulkan. Frame rates have gone from 30 (OpenGL) to 700+ (Vulkan).
Any chance at all that we can get CM2x titles migrated to Vulkan as we wait for CM3x?
An awful lot of platforms are offering solid support for Vulkan. It would be pretty nifty to run CM2x on a RPI4...

I don't want to alarm anyone, but there appears to be a HUGE problem with the Canadian uniforms in CMSF:2.
Have a look at these fellas that greeted me when I loaded up the Cunuckian campaign:

Year 2008. Arid CADPAT - check. C7A2s - check. BEWs - check. Olive green Load Bearing Vest circa Bosnia 1994 ... what in the tabarnak is this?
Alright, drama for the sake of comedy aside, this is a strange one considering in CMSF:1 Canadian troops were (correctly) represented as wearing all Arid CADPAT gear. Where as it seems for CMSF:2 a conscious decision was made to change the Canadian uniform artwork and clad troops in their ancient OG LBVs.
Yes, the Canadians kept using the LBVs well out of the 90's - even surviving the introduction of CADPAT. In fact the initial force into Afghanistan wore Temperate Woodland CADPAT and OG LBVs. Afghanistan c.2002 (source and  source) :

Not long after in 2003, the new Tac-Vests are introduced, albeit still in "Temperate Woodland"; the LBVs are never seen in combat operations again. (source and source) :

Then in 2004 Arid uniforms and C7A2s were introduced. Can you believe they still drove the ILTIS in Afghanistan in 2004? (source and source) :

"Arid uniform - Green TacVest" combo survived for a while, well into Op Medusa in 2006 (source) :

By 2007 however, the entire ensemble can be seen in Arid CADPAT; also issued ballistic eyewear is introduced (source and source) :

Thank you for making it to the end of my brief on The Woes of the Canadian Military Equipment Procurement.
Seems pretty clear that by mid-2008 CMSF timeline the gear would be all Arid CADPAT and new-pattern TacVest ... as it was in CMSF:1.
Anyone have any insight into what happened in CMSF:2 with the LBV's? @MikeyD or @BFCElvis perhaps?
Cheers!

The old flowchart is for the SF1 version ONLY. While the order of the battles and what happens next has not changed, the rest, refit and resupply variables have been modified to reflect the updates in the game engine since SF1. 
While I understand you were disappointed to encounter the exit zone error playing the updated SF2 campaign, this advice makes literally no sense. The updated campaign file is based on the original campaign, meaning the exit zone error was, and still is, in the original SF1 campaign. Not only will some one playing the original campaign run into this issue, they will also miss out on all the other updates improving the campaign. 
I did a speed run of the campaign last night as your comment about this being a bug in the campaign needed to be checked. I ceasefired in the setup phase of every battle not requiring a victory to move on. There was only one battle needing a minor victory to advance. I kept the tanks out of the battle as much as possible and did not suffer any tank casualties. In the Counter Attack battle, I started with 1 tank on the map and more than 3 tanks arrived as reinforcements. Since all the tanks in this particular mission are core file units, you must have suffered a tank casualty in a previous battle.
As for the British platoon HQ units being unable to call for artillery, this is a game engine issue and not a campaign specific problem. The issue has been reported in the official channels and should be fixed the next time a patch is released. Knowing this problem exists, and the importance of timely artillery and air support, I can only recommend doing your level best to keep any Forward Observers alive. There is nothing further I can do on this issue as any further work is above my pay grade.

All of FI is available now.  The Commonwealth module for FB will be a while, so that's another reason to wait on it.
Speaking of which, always wanted to play both sides of a Peiper campaign with British defenders.

This is why I like the idea of allowing the player to play for extra time at the cost of VPs.  The briefing must be clear that the player has a decision.  Hit cease fire at the recommended 2 hour mark or play past 2 hours the cost of 300 VPs (or whatever VP amount is appropriate).  This also keeps a scenario from abruptly ending on a player who is having fun and wants to see his plans finish playing out. 
For replays of the same scenario It may be useful to identify what AI plan the player is fighting against.  For this purpose I sometimes use the following method in testing a scenario (when not on scenario author test mode) .  If the scenario has three AI plans: 
Three small modular buildings with no windows or doors are placed on the players side of the map.  There are at least three action squares (24 meters) between each building.  The buildings are landmarked (the red on map lettering) with PLAN ONE,  PLAN TWO and PLAN THREE.  When the player hits the red button to start the game an OpFor AI unit spawns inside the building with the AI plan that loaded.  A OpFor tentative contact icon will appear in that building.  Or if the player doesn't want to know he doesn't place a unit next to the row of buildings during setup.  So, if the player chooses, he now knows  what AI plan he is up against and if he has already played it before.
Granted, if he wants a different AI plan he now must exit the game and reload.  But for a player who's not comfortable opening the editor and turning plans on and off it might be something.  It's easy enough for the designer to set up.   
Hmm, I think there is another thread about replaying scenarios.  I might repost part of this reply in that thread if I find it.              

BFC is going to go whichever route they choose, but I hope that if there ever is a new generation, that it is Combat Mission as a base game and every module plugs in to that, so that it all works together as one.

Aye I enjoy the logitics side as well - one reason I enjoy large scenarios. You have to factor in way more 'higher' level stuff. I've not long finished up a PBEM and the greatest challenge - as well as my opponent throwing a spanner in at what felt like every turn, was co-ordinating a large force to force a crossing over several defended crossing sites. With the key the one I could cross (that was not under as much fire as the others) was a muddy ford... I'd Tigers also but did  not dare risk em crossing the mud, so they had to wait till i managed to seize a heavy bridge so they could cross. Making that decision in itself was a brill part of the mission! My oppo did a good job though of reducing my traffic management issues by winnowing down my force... 

Correct.
The last patch for CMSF was near a decade ago. You mentioned being bewildered that CMSF was always undergoing some change which the release of CMSF2 only further compounded.
I was simply curious as to:
1) where you were getting your patches for CMSF as the only the last one I applied for it was 10 years ago; and
2) what feature (or mechanic) in CMSF2 is causing your distress? The core play mechanics to me seem to be identical to every other CM2 tittle (WWII and Modern).
I'm wondering if I'm to only one who simply refers to weapon/organization chapters in a given manual as the UI/core hasn't changed much since CMBN was released.
I'm only trying to help by first understanding what is causing you to have to continuously relearn the game.
 

There's a whole bunch of them available for download in a thread in the 'Maps and Mods' section of CMFI - They're still a bit messy, in terms of missing descriptions, thumbnails etc, and missing AI plans for both sides (usually just an AI plan for defender), so I haven't put them on the Depot.
Over Christmas I'll try and finish them off properly (there are a lot of them!), and upload a big map pack to the Depot

Where are you getting such patches? All I ever manage to get are minor corrections...

(G) You forget all about kicking in the door like an action hero, and instead you use smoke, move your Bren guns into cover with LOF within 150m of the buildings. When the smoke clears, you shoot it out with the Germans and then once they are dead you enter the builing. 

I understand what you are saying from a historical perspective, but I just think using a short-barrel Pz III against a T-34 would be very similar gameplay experience to using a Sherman against a Panther.
It's possible I'm wrong of course.

I'm always playing WWII and I always seem to be in a hurry. 

There's also a third option. You could play PBEMs but not participate in ladder matches. I think that's the best way to find calm and mature opponents - no offense to anyone who plays ladder games of course.