Theymos is almost certainly not going to do this because feedback isn't relevant to most discussions. What makes you think someone with positive trust isn't going to scam you also? People rely far too much on whether people have green or red feedback already and treat it like it's either a death sentence or a mark of ultimate trustability when it's not. If red feedback is shown everywhere then people would just use that to discredit certain peoples posts when it's probably not relevant.
I know this question was raised before but I want to try to add some new details.
I think trust ratings should be visible on all boards for these reasons.
A) Most scammers promote their scam on their signature. Consequently any of their posts is potentially dangerous if their tag isn't visible.
Then check their feedback before you do business with anyone. We can't be responsible for babysitting everyone.