That is just one bidding strategy that is utilized by some buyers, and a reason I don't like the 15 minute rule. But it worked for the guy who won, and he played by the rules.
The 15 minute rule saved my ass a few years ago when I was going back and forth on a John Nichols graded hammer gun. I was hundreds of dollars over where I had hoped to buy it when I noticed that one of the hammers was a non-matching replacement. What a rookie mistake! It wasn't mentioned in the description, and the pictures didn't focus on it. I knew an original with the same engraving would be near impossible to find. When I saw it, I was high bidder, and hoped the other guy would bid again. To my relief, he did, and he won. About 6 months later, I saw that he listed the same gun, with a starting bid hundreds less than he had paid.
I've been amazed by the psychology of auction buyers for years, whether they were live farm and estate auctions, or internet auctions. I don't care to stand in the sun, or in sleet and cold all day, just so I can end up paying more than retail on a used item. But some folks do. All you can do is be entertained by it, and hope for the days that the fools leave early or don't show up. You'll never figure it out.