Its potentially important for members of the site, I agree. Say I wanted to use the name SaltySpitoon as an artists pseudonym as well as my handle here, and I was an active scam buster, and I was painted with all kinds of negative feedback from people I had picked fights with, I wouldn't want it viewable by anyone who didn't have a complete picture as a member here. If you don't have a complete picture of how the trust system works, I don't think you should have access to it one way or another.
On another note, aren't false positives just as likely as false negatives? If you aren't a member here, I could argue that you might not be aware of the practice of sock puppets leaving fake feedback. What if a new member sees positive trust from all of the scammers aliases?
My main point is that having it not visible at all, is less harmful than having it visible and misleading.
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The Google issue can be mitigated to some extent by making the feedback pages non-indexable. So if someone merely googles your nick they won't see the derogatory info pop up directly in search results. They could still click through and see it but even today they could create an account and see it. Bigger fatter warning next to untrusted feedback could help. Perhaps don't show untrusted feedback to guests at all.
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I don't see how this would be necessarily worse than fake accusation threads such as " is a pedo / pill abuser / etc". Those are already indexed by search engines and tend to show up first.