I am sure this kind of stuff happens all the time... phone calls and e-mails are easily trumped by cash in hand. After an hour plus drive, one of my phone deals went this way:
Bing Bong... owners wife answers the door...
Hi ! I am here to pick up the TV in CL.
Sorry the TV has been sold.
Yes, I'm the guy that bought it over the phone about 2 hours ago.
No... you are the guy that is going to be angry !
Door shuts.
jr