When they don't move, I just tower over them for a moment and watch them come back and then skedaddle. The only character that going afk is absolutely necessary is necromancers, because once you log out you loose your minions, which I honestly think is stupid. I have to take a crap but can't log out and risk a death because of it, while anybody else can log out no problem. Take into account that on a good day, it takes 45 minutes to raise 5 zombies if you don't fail one.
As for AfK kills, it happens, and if they didn't log out then it's a sad story for them, same for if I die afk. I try not to kill afk people, but it will happen, don't wanna die afk, log out.