A couple of questions:
1) what if the person who left the first negative rating gets removed from DefaultTrust, so that for most people their rating is no longer defining a border, but still is for some?
2) what if the negative trust defining the border gets removed by an administrator (because their account is suspected of having been hacked, for example); the border no longer exists, so am I expected to remove the positive rating I left responding to the negative (bolded, above)? Or should I leave it in place?
There's no harm in leaving extra positive trust ratings. You can keep them or not, it's up to you.
It is a bit of an issue that trust ratings are subjective. Probably this is a flaw in the trust score algorithm, but I'm not sure what to do to improve this.
Also dooglus is more or less talking about tsp, where he has given a more or less a reputation loan, should that be considered a valid trust feedback?