I wonder what a Legendary account would sell for.. Haven't seen one yet for sale that I'm aware of? (Not that I agree with this mind you)
I would like to think that most of us respect the integrity of the community enough to not sell accounts. It's a pretty unethical thing to do, unless the ID of the sold account is made public.
No way to prevent anon sales, though. Some people just suck.
If the account is not used for scam, I personally don't have a problem with people selling their accounts.
I don't think scamers see a lot of value in buying an account for 0.8BTC to scam anyway because they can only do one scam with it then the account will get negative trust.
Scamers have many ways to steal so they can certainly find a way to profit from buying a Hero account and try to scam many persons at once but they have to "invest" 0.8BTC in their scam and they may get a negative rating before they succeed their devious plans.
Nobody should blindly trust a Hero account anyway because it could be compromised somehow.