All I can say to that is you need to deal with it ICly, it's an IC action after all, even if you (incorrectly) believe it to be done with OOC malice. Call the person a thief, slander their name, get people to refuse them from quests if you really hate them that much, beat them up.
You're putting words in my mouth, I never said it was OOC malice. I feel like you're taking this rather personal.
I dealt with the problem in character for a time, I would weather the storm and wait for that character to die off. But I grew exhausted of dealing with the same problem from every new character made by the same players. That's when it suddenly dawned on me… The selfishness is not a character trait that was designed as part of the character... It's a flaw of the player's personality that was bleeding over into their characters. The players themselves we're just selfish.
I played support characters and rather strong ones that held parties together. I was tired of being bullied.
The second I made Wing Pelton... A PVP based character for the sole purpose of making sure people couldn't continue to bully me and call it "in character" I realized that I had lost sight that this was a Roleplaying server.
So say what you will, I tried to handle it in character. When that didn't work I handled it out of character.
I stopped playing.