On my recent trip to Montreal for the IEEE, I had a weird credit card experience. I went to pay with my American Express card, which has a silver magnetic stripe on the back. When the waiter brought back the check, he had an old-fashioned carbon copy receipt.
He explained that AmEx cards with a silver magnetic stripe, like my Costco cash-back card, were of a newer design, and the process for reading them caused their card processing machine to crash. The could process the new-style AmEx cards in the machine, but the transaction would crash it and they would need to reboot. Unsurprisingly, it’s not a very fast machine and the reboot time is lengthy. Therefore, while waiting for AmEx to supply a patch that fixes the bug, they were running all the new-style cards manually.
The moral of the story: all software has bugs, and software is everywhere. Therefore, expect to find bugs everywhere, even where you least expect it. (A friend who was doing research involving automobiles once told me that essentially all new automotive features are software, so it accounts for an increasing fraction of the cost of newer cars.)