Proposition - create a special thread with PayPal emails, used for fraudulent refund / chargebacks. Sellers can use such list in own systems, as PayPal don't allow to block customers but many wordpress plugins have this feature. User from BHW can always explain and delete his email from list after contacting moderator with proof that his refund wasn't fraudulent like "item not delivered". In my experience, most of buyers who are making fraudulent refunds, visits BHW but without account. It's very hard to catch pro scammers After someone add email, moderator edit first post with list of emails.