Selling accounts actually
is discouraged, according to forum rules:
18. Having multiple accounts and account sales are allowed, but account sales are discouraged.
And you also stated that in OP.
To sell bitcointalk account, it should be discouraged, it is even included in bitcointalk unofficial rules number 18 but does not mean if you still think you have to buy already ranked account but if anything happen to the account that got your bought account not able to access this forum again, you will have to face the consequences.
Besides, bought accounts are also tagged when they are caught. What else would you like to do? It's against the rules and cheaters are revealed through adequate feedback. Is there anything else do to

Lol, good question indeed!