As I said this before, there needs to be a set of certain rules, guidelines being posted by admin himself, then in time people would support and abide by the rules. Problem is when you allow everyone decide on everything individually, that can't end well.
However there is a question of who should enforce the said rules? Well, of course responsible DT members. We all know when symm wiped his trust ratings, he had a bunch of good ones too, but did the entire community got scammed by those who were tagged by symm? So if you see someone on DT with %80 "good" ratings and %20 unfair, unjustified ratings and close your eyes to their misuse, well you have been just fooled by a person who knows how to play the system in a way that people wouldn't touch him because of "good ratings". I think if you can eliminate that notion of being untouchable, then nobody would dare to game the system like that.
I'm not talking about myself, I'm already done with my main account.