You could easily track the paypal email used to make the purchase (add another column in purchases table etc.) , then use the RefundAPI from there to check if it has been refunded
The title says it all.
Basically, we're worried about developers (resource owners) scamming - and the only way to avoid this would be to force people to refund said buyer before removing them from the buyer's list.
I/e Someone tries to remove a buyer and they get an error message along the...