that is correct, although the impact on gameplay is quite minimal and they will function as you would expect a basement or cellar to function. mostly a place to hide.
http://www.armchairempire.com/Reviews/PC%20Games/combat-mission-shock-force.htm
it is a nice thing to have in ww2 but not necessary for modern due to the super fast tot of elite spotters. red hurts for the lack of them, though.
i think they mean "Geared towards single player", since that's obviously where most of the effort went in the cmsf series. the campaign maps in the british campaign for example are really amazing jobs but the multiplayer can't access them.
personally read enough accounts of Stuarts using the "squirrel gun" to shoot infantry positions up particularly reinforced defenses.
it was mistake to use "blast" for the weapon in game. the charge is to help promote frag through structures such as stone.