Minimize the risk of detection
Something as innocent as when was the last time that the system asked the user to change his password could be used by him in his advantage. If that site ever gets taken to court, they will have to list their total transaction history, but keep the users, i.e. names tied to accounts secret due to countries citizen privacy laws. Remember this is not 100% fool proof and I can not tell you if I have used any buy sof gold services but it will minimize the risk of detection post purchase.
