Originally Posted by fowl intent
Sounds to me like the buyer knew the seller made a mistake, and did everything he could do to capitalize on it. Why else would he have immediately gone and gotten a cashier's check to pay off the entire balance when he signed the new contract.
The dealership screwed up twice, once on the initial mistake, and the second time by getting law enforcement involved in what is really a civil issue. But for buyer to prevail, he has to come to court with "clean hands", and I don't think he has them.
The buyer might have suspected something was off, or he could have thought they were giving him a good deal to make the sale. Either way, the dealership signed the contract and accepted his money, they screwed up and it's their problem. The buyer's actions might have been morally questionable, but legally he owes them nothing.