This happened a couple weeks ago at a sit down restaurant that my family and I like to eat at. The bill came out and I put my Amazon Prime Visa in the holder to pay. Which, by the way, after visiting Europe and Canada, why the hell do we allow this to happen in the U.S.? In those places either the server brings a mobile reader to your table or you pay up front and your card never leaves your sight.
Anyway, the card came back to me with a receipt to add a tip and sign. The receipt was for our order but I didn't notice at the time that the card was someone else's Amazon Prime Visa. In fact I only noticed later that night when I got my card out of my wallet to pay for something online.
I called the number on the back and told them what happened. They gladly reissued me a card but they wouldn't even take the information for the other person's card that I currently had. It makes sense, the other person would eventually figure it out and get a replacement on their own.
The really interesting thing, though, was what happened when the other person left that restaurant with my card. They went straight to Walmart and tried to make two separate purchases each for a couple hundred dollars. Both of them were automatically flagged as fraud and denied, though. This actually kind of blew my mind. Visa allowed the nearly $200 charge for dinner to go through, but it somehow correctly surmised that the charges at Walmart just a block away within just a couple minutes of having dinner were not made by me. This was just before Christmas so big expenses wouldn't have been out of the ordinary. I can't think of any other time that I had made a couple of big expenses like this that I had trouble with, either. The number of times my actual purchases get flagged as potentially fraud is like once or twice a year across all of my cards. And half of the time it's just them sending a request to verify that I had actually made the purchases that already went through. This had happened at least an hour before I had called Visa, too, so it wasn't as a result of that.
So I guess this just serves as a reminder to make sure you get your card back each time a server at a restaurant takes it to pay the bill. This is the only time it's ever happened to me, though.