The trust system here on Bitcointalk is severely broken.
Any user may give another user a bad trust rating. For example, here, a user was left a negative trust rating purely for a personal argument:
"Shits on anyone who doesn't agree with him. Not smart enough to argue a point so he calls names. Possible Tourette patient."
https://bitcointalk.org/index.php?action=trust;u=367278
A while ago, the creator of Dogecoin was left negative trust on this very forum.
It is not uncommon for users to be extorted out of their Bitcoin because of this very system. [1]
A senior member's high yield investment business came to a tragic end when he suffered from negative trust despite no evidence that he stole any Bitcoin at all, but rather, because they "thought" he was going to steal them (See: Minority Report).
Also see: BTC-Backers
The system is not just limited to flaws in negative trust either. There are many examples of positive trust ratings being uselessly given out, when no trade was carried out at all. Consider this profile, the "trusted feedback" is full of ratings like these:
"Vod has the ability to spot scammers from their first post, making the forum a better place"
"Scam Buster! Good guy for the community"
"Very trustworthy, helps prevent people from being scammed."
"The neighborhood scam-buster.
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
Don't get me wrong, it's probably a very good thing that he's a "scam buster", but it makes no sense to leave that as trade feedback. Such usage of the trust system just makes the "Risked BTC Amount" column ineffectual.