It certainly is a game. It's an attempt to construct a game of 20 participants bidding on a scarce resource (you, the buyer) with specific rules. And would likely work, unless say, a few buddies happened to chat over beers and the subject of 'that crazy guy on the phone' comes up. The element of scarce information will then break some of the 'rules', negating much if any of hoped for strategy.

I like your approach much better, going in with maximum knowledge is key.

The one I've read about and wish I had the nerve is to get a few thousand in hundreds and right off spread it out on the table in front of the salesman, say this can but yours today, just hit my price.