I would like also to add :
With this trust system it is so easy *abuse it* so I think we need new change , or better modify it completely. Because I've seen a lot of these type of threads ( it is always the same story).
What do you suggest as an alternative? I cannot think of a feedback system that is flawless or foolproof to abuse but if you can some up with one maybe it will be considered.
there should be limits as to how many people can be on your trust list if you are on level 1 default trust. This will prevent the privilege of being on default trust being given out as a "thank you" for your customers.
There should be different formula for calculating positive trust if multiple people give trust feedback that are not trusted by different people. For example if everyone that gives you positive trust are all trusted by badbear then each additional trust rating by someone on badbears list should count for less while someone on theymos' list would count for more. You should not be able to receive "green" trust unless you are trusted by people that are on at least two different trust lists.
Negative trust should cause a profile to turn "red" at first with one scam report but would go away after n time without a second scam report. This would prevent someone from being able to continue to scam but would prevent someone from abusing the trust system and would force scam reports to be community reviewed (and a 2nd person agreeing on default trust) after a scam accusation is opened (as it should be after giving negative trust)