I don't see why people do this. I saw these two coins sold earlier tonight, please note the prices they sold for at a Goldberg auction last year as stated in the listings: http://www.ebay.com/itm/AVC-1920-C-...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557 http://www.ebay.com/itm/AVC-1919-C-...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557 Now, it takes literally 30 seconds of research to see that these coins don't sell anywhere near those prices on eBay. Why would anyone do this instead of just consigning them back to the same, or other, major auctioneer where they sell for 2-3x.
The only conclusion I can come to is that they didn't sell at Goldbergs at the quoted hammer prices. They were shill bid at Goldbergs by the owners in order to quote "values" that would drive bidding at the REAL auctions, which were on eBay.