In first person shooters, normally, there's no difference between "what you're looking at" and "where you're shooting." Your weaponry is "head mounted" and you're always aiming at the center of your screen.
There is now a general expectation that people that shoot at you also look at you, and, conversely, that if you're playing spy and you're looking at somebody's back, that somebody can't just shoot at you without turning all the way around.
TF2, however, has recently introduced Oculus Rift support and now allows a few lucky (and disoriented) players to look in a direction and shoot in another.
How is this conveyed to other players, however? Do they try to show the body and weapon moving independently from the head? Does the model move just with the head, or only with the gun?