Cash Machines (ATMs) Make Mistakes and They're Proprietary Software
Correcting mistakes is a colossal challenge
"Recently someone asked me why I am willing to use checks that were printed by a bank which surely used nonfree software to do it," Richard Stallman wrote yesterday (or updated an existing article). A week earlier I spoke to Mr. Alex Oliva about this article regarding my bank, which is being subjected to "Enshittification" - a term both Mr. Oliva and I habitually use.
A very long time ago Dr. Stallman explained that using an ATM (or "cash machine" in typical UK vocabulary) that runs nonfree software is quite OK given that it is not your own machine but something you merely use to get a job done. It would be better and more secure if high-street banks adopted Free software (like BSD or GNU/Linux) for their machines - some of them already do at the operating system level - but the used interface is usually proprietary, so they rely on shallow and secret audits for security, integrity, accuracy etc. They'd rather lie (to cover up mistakes) than admit culpability. A couple of days ago in IRC we mentioned someone who got arrested after he had turned ATMs into 'jackpot' machines, which meant he and his friends withdrew over $100,000 from machines. They got caught. Some do not get caught. Then the media might not even mention it ever happening.
I myself don't use the ATMs very much. I pay with cash almost all the time and I retrieve money from ATMs only a few times a year. I don't use "cashback" at shops as doing so ties your purchases to an identity.
Once upon a time, when Wilko still existed (yesterday we went to the shop where it existed before going out of business) the cash machine there gave me the wrong sum of money. I was short-changed by DCPayments (ATM company) and had to go through lots of trouble to correct it. That was more than 9 years ago [1, 2], but ever since then I've been extra picky when it comes to ATMs. They're all proprietary, they do occasionally make mistake (always double-check!), and when mistakes happen there's usually nobody to talk to and they don't wish to believe the customers. The first such incident happened to me around 2001. It happened around Rusholme when I was a student. Disbelief from staff was already a problem.
One might wrongly assume that the tasks done by ATMs are simple enough to always get it right. It's still a myth. ATMs make mistake, just like Fujitsu did. █