I dont Know about recrewing abandoned vehicles but my current PBEM adversary has a great line in crew forward observers even got a single crewman from a disabled stug to pin one of my anti tank guns for about 30 seconds. fortunatly a nearby crew of mine killed him by then. It all depends how you play if you want to send your crew on a march through enemy lines to weed out his hidden units or not, Im in the not camp and leave them in cover or ask them to leave but you cant legislate against the desperate.