Superauctions is the company that got the rep for having the buy-backs. It would be safe to assume that's still happening. I find it kind of sleazy myself. The owners of the machines will sit in the audience and get into a bidding war with a real buyer, driving the price up. Personally I don't think that's ethical, but in some states it is legal. I think this is what reserves are for. If the seller doesn't want to let his game go for a certain price, fair enough, but shill bidding really annoys legitimate buyers.

On the other hand, I understand the auction companies have to make it appealing for the sellers to participate, but I'm not convinced that's the best approach. In general, I'm not a big fan of pinballs at auction. Here's the last experience I had at an auction with pinball games: http://pinballhelp.com/talking-too-much/