Please consider adding this information to the stickies for newbies OR (even better) cancel this Feature and ALWAYS show the untrusted feedback by default! This should really help keeping scammers out, since a lot of them only have untrusted feedback.
That really doesn't sound like a good idea with the amount of trolls and butthurt people this forum has.
Take a look at my feedback for example. 9 untrusted negatives, and 1 positive one. This would make my feedback -99 or something ( not entirely sure how the trust system calculates that..?) While i've never scammed anyone.
What i'm saying is that there's going to be a lot of false positive cases with the system change you are proposing. Inaccurate ratings or revenge ratings are extremely common.