I think if there is agreement in this discussion that past mistakes will be forgiven...
I feel you're over reaching in your expectations of others. Especially where scammers are concerned.
I feel if a person who is inactive for say more than three months, then their trust feedback should "decay" back to neutral over a predetermined time frame. Regardless of whether or not they then come back online in which case the trust feedback paused decaying, but doesn't revert to either positive or negative as the case may be.