Who has told a buyer that what you have is not what they need?

This happened to me just a couple months ago. I had my A100 for sale, and a guy wants to buy it. We meet up. Turns out he is a local police officer and wants to turn this van into the Mystery Machine and give sick kids rides around the hospital parking lots.
I go over things with him on how to drive it and ect. He pays me cash and we go our separate ways. I don't get 2 miles down the road and my phone rings. Its him , telling me that he is broke down on the side of the street. I go to his rescue and find he has overheated it and blown it to pieces . He put it in 1st gear ( automatic ) and pedal to the metal till it started throwing parts out.
I just gave him his money back and towed it back home. Some people are just better off sticking with a new vehicle.