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.
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.
That is definitely wrong. What if someone pulled off a massive scam and the character behind that account is not trustworthy whatsoever? Just go silent for a year or two and come back with neutral trust on that account? What if somebody with +20 trust goes silent for two years, comes back and is obviously the same person? Start from neutral trust? No, that can't be right. It is even asymmetric in the effects it creates for the forum and will to some degree lead to adverse selection. The incentive to work for positive trust decreases while the incentive to profit from negative trust increases.