I believe you can set this up and more in your account customized rules for bidders. Reject bidders with feedback less than 1, and also set up rules so when an item sells the buyer must pay immediately, or the sale does not go thru. A lot of rules can be created and established for your account. I especially like the "immediate payment required" rule. Saves the hassle from flakes buying your stuff then backing out of the sale for some lame reason. i.e. my cat needed an operation. My grandmother was in a car accident. I lost my credit card. And my favorite, I was drunk and didn't know what I was doing.