I think you've got it spot on dude, it's all about communication. If you're joining a massive session where people are racing or going off and shooting randoms then you should be prepared to die from just about everyone.
We'll draw a line through this now, so......
When joining up with other people, say to them that you want to build up money and don't want to be killed. Then the other people should respect their wishes and kill everyone but them. Also no saying you don't want to be killed only to go up to someone and kill them. You you do have issues with people killing you when you don't want to, speak to them privately about it. If you can't come to an agreement after that, then don't game with each other.
It shouldn't be as hard as all that but it is (for some reason), so forget it all and now lets go and have some fun and remember we're all friends here, a game definitely shouldn't be coming between us!