Edit: Also what you're talking about is more or less everyone being included in DT
So again, as people have said, what prevents me (or anyone else), from creating 500 accounts and giving you (or anyone else) a neg rating with each account? Then everyone would see those ratings and you would be considered untrusted because supposedly 500 people have negged you. What prevents someone from doing that? You say that giving trust requires trades, but how is that enforced?