The limiting factor is the buyer's reputation with his credit card company. If he is repeatedly doing chargebacks people hopefully a credit card company will notice and not take his side or better yet, not issue him credit. The idea is that credit card companies also do not want to have this person as a customer, and probably this is a new scam he dreamed up, not an ongoing one.
Why would the credit card issuer not want that customer? Each time he issues a chargeback, they're getting paid a chargeback fee by the merchant (PayPal). It could even be profitable for the bank.
