I guess as much as we hope to send our beloved cars to good homes when the time comes, whatever happens thereafter is beyond our control.
I would be very annoyed if the person claimed to be a fanatic or spun a story to get it a better deal only for it to end up at a dealer the next day... but at the same time, what can be done about such situations once money has traded hands?
Isn't this how the vast majority of M/x35/Z <insert any special car here> stories end?