It's been a while since I suggested such, but every auction should probably have something to the following effect:
"If you have are not yet a Full Member (3-coin forum rating), or have a negative trust rating, or are on my ignore list, your bids will not be counted unless a full backing payment to 1XYz1234568lhugfTGfkif22334 accompanies your bid. Any bid increases by such individuals must also be paid in full before they are respected as real bids. If such bidders lose an auction, all sent coins will be refunded to the address they were sent from."
Yes... there are a couple of rules and suggestions that could/should be included into the tutorial to make auctions work better.