How about an escrow through pinside? A flat fee of $30 (or whatever pinside thinks is appropriate) per deal and clear rules about the rights and obligations of buyer and seller, like who pays for return shipping if the game is rejected. That would eliminate a lot of frustration and uncertainty on both sides, save money on the transaction and generate a source of revenue for pinside.
I recently had an E-bay buyer bail out on me because he found a better deal or whatever. He claimed that the shipping cost of $740 was too high. When I called myself the shipping was $433. I told him and gave him the quote number but he made up a new lie to cover his initial lie. What did E-bay do about a non paying bidder? Absolutely nothing!