Well, I would kill on sight almost any armed player I see, unless they for whatever reason have the chance to kill me and decide not to. However, I have only so far killed one person (turned out to be a bandit) and got a few shots off on some guys. It's the way I play, I move around a lot and rarely wait for players. I guess I must be a bit of a dick though, since one time a guy found me, gave me an M9-SD, said thanks and just walked away.