Used to happen to me all the time. As you get more hours in the game though, you will be able to tell better who you should trust and who you shouldn't. Not gonna lie, some people are very convincing and seem very friendly but will still kill you. I've been playing for a while and have been killed by bandits countless times but I still choose to play as a hero/friendly guy because I think that's what I would actually do and to me it adds another aspect to the game... Help everyone you can and shoot the guys who shoot you first. I've tried and being a bandit is just boring to me all you do is find good gear and shoot people. The cool gear is cool but that's it you don't get to make other people happy, you just ruin their experience. I have no idea why so many people like to be a bandit,