That is a great theory, the main issue with the trust system is the misuse of the negative trust in general, only a handful of people stick to the proper use of it , the rest use it for everything they see fit and of course it's always "justifiable" to tag someone you don't like, there is a dozen of "reasons" for anyone to tag anyone for the sake of it.

However, this approach won't solve the problem IMO, some people will keep waiting for next month only to get their "vengeance", the best approach about this is to randomly select 5 members who "give someone negative trust for some stupid reason" and blacklist them from DT forever, then everyone will start using the trust system the way it was intended be used.