In a world without consequences, I think most people would be pretty fucking vicious.
However, I don't think these games are a mirror to your real nature because of the other differences the game world creates. Most importantly, you're immortal and can go do something else whenever you want. Death is ultimately trivial compared to real life. Sure you lose your stuff, which sucks, but you don't cease to exist. The reverse is true for those you 'kill' in game.