He probably means can you prove they were legitimately purchased? Where are you purchasing them from and how can people know they wont get hit with a chargeback like many people do buying cards on here?
This I think is a misconception. Many people do not get hit with chargebacks. When I question some one I feel that it is more because I feel bad thinking that some one is getting screwed. Basically if you have no morals I doubt that you will encounter a chargeback especially if you use it quickly. If you really want to be sure make him buy you something and then release escrow when you receive the item. The seller should only deal with trusted users when using that method.
amazon sends you a bill, and if you don't pay up, they blacklist your address.
