lol, i remember when i first saw "bidder 1" and she/he kept out bidding me. i used to think "that biatch" until i realized it was a privacy feature. not one of my smarter moments!
Actually if you go to the bid history and click on "Bidder 1", "Bidder 2" etc. Ebay also gives a lot of extra info about the bidder itself, e.g. if he/she has already bid on items by the same seller etc. etc. I guess this could prevent shill bidding?