I have this happen on occasion but it's one of the risks with auctions which I tend to prefer. There are a number of problems with auctions some of which eBay could easily fix like requiring immediate payment when the auction completes. However, that could potentially also have consequences should the buyer find it cheaper elsewhere or change their mind and cancel the order.
There are, as others noted, the sport bidders and competitors out there that do this for fun or to jack up prices so their items look cheaper. It is easy for these individuals to do so because eBay provides little scrutiny over the creation of buyer accounts. I could setup a dozen of them in 5 minutes or use a guest account and a VPN to mask IP and location information.
The other issue with auctions is you can never tell what happened with the buyer between the time they placed the bid and the auction closes. They may, as I noted earlier, have found it cheaper elsewhere or changed their mind. You can bet the buyers that purchase a BIN item that has immediate payment required is sitting at their computer or on their phone. The bidders may have died, had an accident or family emergency or had a natural disaster hit their area.
I would much rather deal with the non-payers as opposed to having to deal with a return from a BIN sale where the buyer files a NAD because that is the easiest way to get their money back and in some cases retain the item.
