I think a lot of people, myself included, tend to forget that most people don't drive these cars all that much. Especially if we're about to sell them. Then the new buyer goes out and drives the car all over the place because it's new and fun, and issues that have been lurking pop up. Yes, sometimes the previous owner is a shady bastard. But sometimes they may not have known that a bunch of crap was about to go wrong because they'd had it parked for 6 months. Same stuff would have happened to them if they dragged it out and put a few hundred miles on it all at once.