I always try to communicate with them to find out if they are friendly or not. When I'm too far away I just observe them for some minutes and try to avoid them when I'm not 100% sure that they won't shoot me. I guess killing is always the last option I use. Sure, i killed some players out of a shock reaction or when they shoot at me. But I'm not a bandit that camps on towers with his sniper and just kills senseless everybody he sees. I just hate those players.