Yeah, it happens.
I also know a guy who sold an antique car to someone (who'd come out to look it over) who said he'd come back to pick it up and never did. He called the phone number he had several times, and nobody ever returned his calls. That was about 5 years ago and he feels too guilty to re-sell it even after all these years (something that many think is nuts, but I can understand).
In the 90s, I got a ride in a warbird for over an hour and half
in a formation, on an agreement I would provide a A-2 jacket to the pilot painted with the art of his choice on the back.
Got the ride, gave my info out-
-then,
nothing.
Maybe he lost it, but I didn't get his contact info in that pre-internet era because it didn't occur to me that he
wouldn't call or write to collect.