What matters is if TF used the trust system in accordance with its rules. According to theymos,
On feedback pages, you can leave trade feedback. There are no rules for this
Therefore, TF can use feedback for whatever he wants. If it becomes frivolous, then people will ignore TF's trust or the entire trust system. Action does not need to be taken by the trust system admins.
Since I tend to be very conservative when it comes to deciding if something is unethical, it sounds like TF gave someone .5 BTC because his banning mechanism and bot detection were inadequate, and now he's retaliating through the trust system. However, the OP was gaming the system (coinchat) and not following the rules, and other people would call that unethical. TF would go so far as to say that it's stealing! It's hard to determine if that makes someone trustworthy without a definition of trust that everyone agrees on.
Thank you very much for a reasonable and thoughtful response. I really only have two small points of disagreement. The first is that my total withdrawl from coinchat dont amount to more than 0.35, so the 0.5 amount is obviously trumped up. This is obviously part of the argument that you are elegantly deciding not to be involved with but I wish to make the correction.
The second is that while you are right that if the trust system becomes frivolous, users will eventualky ignore it, there's an assymetry here in that some people are listed as trustworthy by default. So when those people use the trust system frivolously, it endangers the system (and their victims) even more. Therefore I believe that the trust system admins do need to reconsider their inclusion of tf on that list of default users to be trusted (or whether such a reified list should exist at all).
Finally, can someone provide a link to a concise description of the trust system and its proper usage?