It's been my experience that the majority of auctions end with bids in the last few minutes or seconds. Some people use sniping software exclusively to bid on auctions, which doesn't put their bid in until near the end of the auction. If I won the auction, I don't think I've ever looked to see who bid the price up at the last minute--it didn't really matter since I got the item at a price I was willing to pay. As far as shill bidding goes, I'm sure eBay can catch someone at it just as easily in a private auction as a regular one, even if the rest of us might not be able to.