KoS is a flaw in human nature, not the game. You see, there are two main main emotions when running into a player. Survival "I have to kill him before he gets a chance to kill me" and greed, wanting to advance in the game "I've seen this guy first, I could call him out as friendly, but I want his stuff" to get better gear, once again increasing the chance of survival for the party that comes out on top. Basically there is nothing to earn from not killing the other player on sight, (gear wise) but some people believe (Myself included) that comradeship is far more important than a shiny new gun. TL;DR people probably value your stuff more than your help.