I don't think suchmoon should get tagged for buying one of Bruno's accounts. Suchmoon does have a decent amount of trust, a lot of merit, and is on many people's trust lists. If someone was looking from the outside, and saw suchmoon do something, they would reasonably think, based on her stats that it would be acceptable to engage in similar behavior. Suchmoon is not the only person who has bought/sold forum accounts that can be described this way.
Except I didn't buy the account. But you're right, if this sets an example that it is acceptable to engage in similar behavior, i.e. help someone out and prevent them from doing something ill-advised - that's fantastic. And I don't mind getting red-trusted for it.