I often rest the very bottom of my stock very near the top of my shoulder, it's a pain to shoulder the full stock on my full shoulder with an Osprey on, and when no one else is going to the effort of doing it properly either, it just seems like a disadvantage. Brings the sights to your head, instead of head to the sights, easier, faster, more comfortable; the only reason people don't do that with real steel is precisely because of the recoil, if real guns didn't recoil, then all these "shooting stances" would be totally different.
I've never seen anyone hold anything like a bazooka though, not ever. When I show my guns to family members they tend to tuck the stock under their arm pit and then try to become on-the-spot contortionists to get down the sights, or they'll do this really weird thing where they lean back a stupid amount and hold the gun out in front of them, as if the sights only work from 3ft away lol.
The guns have no recoil and we're playing a game though... Who cares? Unless it's dark looking down the side of the gun is often just as easy as sighting in, sometimes easier because you can see the immediate effects of the hop better.
I'd expect everyone to act accordingly at a milsim even though, it wouldn't be much of a military simulation if no one was doing anything the correct, real life way.