One of the tricks is to use a sniping software. Then set it to bid at the last second. Let's say your actual highest bid for a black Military would be $150.00, you would then type $15000.00 into the bid field. Then when the auction ends, you decide if you actually want to pay the winning bid, and if you don't you claim you meant to bid just 150, and typed the wrong amount in. BTW, I have NEVER done this, and never will because I believe it to be dishonest. However, I do believe some people have used this tactic against me. Thats why I always bid what I am actually willing to pay, but when I am beat by only one person, I send the seller a message saying if the winning bidder doesn't pay, I will still pay my highest bid. It saves them the re-listing fee.
On a similar note, Ebay is changing its policy of letting sellers give buyers negative feedback (or any feedback actually). I think this is stupid, because most of the problems with non-payers are created by a few people, and who cares if they get negative feedback? They are just going to start another shill account. Ebay says it drives potential buyers away when they receive negative feedback. So? Don't you want to keep crappy buyers away? Why encourage them?