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Okay, but if we suppose that Alice will buy a positive from Bob (he is in the defaultTrust list | 2). After Alice will tell that Bob is selling positive trust... what do you think it will happen?
Why should anything happen? The Trust is mine, I have earned it, I can do with it as I choose, so I sell it.
There are no rules against selling Trust, I have delineated some plausible scenarios how bought trust could be used ethically, so not sure what your objection is?
What happens to Bob, a seller of trusted accounts, if Alice decides to rat him out?