Good arguments on all sides.
The "feedback levels" right now represent in my mind (possible the help pages should be updated):
Neutral: a poor experience with a trader, that might be subjective or not, that caused a bad communication, slight delays, a bit of stress, but in the end was resolved without loss of value or too much aggressive fighting. We don't interfere with these, you can say what you want, if you think you don't deserve it we won't do anything about it anyway. This does not influence your positive trade percentage at all.
Negative: a very poor experience. Whoever receives this would be aggresive, dishonest, using obscene language and threats. Other people with negative ignore their trading partner, ignore the admin emails and are generally unreliable. There is still no material loss here, no cards stolen.
The problem in the past when we were not 'policing' feedback was that some people leave negative out of spite, they lie about it, and do things to mess up trade histories of good and honest traders. We did not really want to get involved in these kinds of discussions, but the truth is it brings down the value of the community and pisses off honest people. And we should protect those kinds of people for the community to foster.
While we did not police feedback, we still got emails to support@deckbox.org from people receiving unfair negative feedback. So we still had to do an investigation and judge the situation, only it happened behind the scenes. And while some people did send us emails about it, and we solved it, others when getting to score +4 -1 after 5 trades, for no reason, and just left the site. So it seemed like an official process was needed, as negative feedback is (for good reason) regarded as an important indicator.
Maybe we should clarify to people that although there are stricter rules for negative feedback, it does not mean that person is a scammer or a thief. (If he's a scammer he will be flagged as one and banned). It just means that one particular trade did no go smooth and he was difficult to talk to.