Yes, they are aware that something fucked up will happen, but the main point is, it's not on their free will. So "did they expect it to be table service dinners and fancy cars or something?" just got thrown out of the window, as it only applies to those who freely joined the war, and as you suggested, perhaps expecting nothing serious. Right? The ones who didn't join the war on their free will know that shit's going to happen, otherwise they won't need to be forced into the war.