[swarmee]

I never realized in 2009-10 that PWCC permitted consignors to have a secret reserve bid, presumably against eBay's Terms of Service. Interesting.

Well, an easy thing for the people who identify shilling in his/any other auctions, is for people to report the listings to eBay and PWCC via the "Report Item" link at the right side under the box and select "Listing Practices", then "Fraudulent Listing Activities," then "Seller is using other accounts to inflate price." If people who care and are being shilled in these auctions would report it every time, eBay will be flooded with Report Item notifications. I am not sure if this would hurt Brent and his business directly; maybe he can chime in again and tell us. If it does, then it may be a solid topic of discussion at the meeting coming up with eBay's employees.

But, once reported, eBay and PWCC can check the auction history since they're being given a pointer to specific instances of presumed shill bidding.

Questions I'm interested in:
1) How often are items for certain sellers not paid for? If that number is over 10% (or on large $$ items), that would be a sign to me that shill accounts are being used and then stiffed, so that the "buyer" doesn't have to fork over cash to buy back their own card. They know you'll relist the card during your next auction.
2) Does your staff actively cross-check buyer addresses with consignor addresses of the same cards? Are they kept in the same line on your spreadsheet/database where they could be easily queried to see if your consigners are winning back their items?
3) If the top bidder does not pay, do you offer to underbidders? If so, this would also spur shill bidding. You could make a policy that you will never make offers to underbidders. Most bidders are wary of receiving "2nd chance" offers, figuring they were bid up in the first place.
4) Can you block/suspend all user accounts with over 5 bid retractions in the course of 6 months and all related (same IP, address) accounts? This would help cut down on overbidding to identify someone's top bid, and then backing out.

So, these are a few of my constructive comments for your discussion with your own team and eBay.