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?
Thats for whoever gave you your trust to decide. If you earn trust and then scam somebody, well you earned your trust previously, why should you lose it? Trust is a dynamic thing, if the person who added you to default trust no longer trusts you because you are doing something shady (selling trust is considered shady) then they are completely within their rights to remove you from default trust. If the person who trusted you doesn't take action, then the person who trusted them can take action, etc etc.