But what the seller doesn't know is that they likely could have gotten more by letting the auction continue.

So the seller loses, the rest of the buyers don't get a shot at it and someone picked one through the back door.

The funniest comment in the thread is "I didn't get this one." Which implies that there are others which have been picked up by people on this BB who bought behind the scenes and had the seller close the auction.

Unless the seller has Buy It Now and is getting robbed, I don't see why an auction shouldn't continue. I've put up items that go for $300 with a starting bid of $10. I have confidence that people will bid what it's worth. If not, then it's not worth that or I wrote a bad listing and description.