Your statement also ignores basic economics. If someone pays $250 to buy an account, if they were to attempt to use that account to scam someone, they would be risking that entire $250, even if they are unsuccessful. They would need to successfully steal $250 just to break even. Someone who buys an account has a fairly strong incentive not to scam with it. Similarly, someone who is the owner of an account that could be sold for $250 would be better off selling his account rather than trying to steal money from a NPV perspective.