Placing prone-fire only MGs behind cover is indeed frustrating, especially when you are in a building. In Normandy maps, there are some static farm house models where it has quite a large hole at the bottom floor of the building, big enough for a crouching player to get in. The holes are often facing a wooden/stone fence, rarely placed for someone to snipe from that position.
I often camp there when defending a flag. But my position is extremely angled to the wall side at my disadvantage. Thankfully only bots do wallhack and detects me instantly. Most human player rarely checks their left and right when passing through that hole.
