It's fun to watch the same few bidders peck away at each other in $50 increments until the price is out of the dirt cheap range. Then, of course, those chiselers will all be blown away by a bidder who makes one bid in the last few seconds of the auction at a more reasonable price.
Private bidding means shill bidding.
Bidders identities were hidden years ago.
If one wants to be crooked there are plenty of ways to accomplish that.
Besides.......there is only one bid that counts........ ;)
Ebay hides all bidder identities. They knew that people were offering similar items to non-winning bidders and skipping the ebay fees, so they made it impossible to see who's actually bidding.