My guess is simply superstition. I don't know if this is true (I heard it from a local), but for decades there was not a single ATM on the Falkland islands. Th

My guess is simply superstition. I don't know if this is true (I heard it from a local), but for decades there was not a single ATM on the Falkland islands. The local bank said ATMs just don't work on remote islands. So a Stanley petrol station took the matter into their own hands and just bought one. ATMs don't care if you're on an island, you just plug them in, put money in them and then people take it out. I can at least verify that that part is true because I was there, saw the machine and got money out of it. Another personal anecdote is an industrial application where safety critical updates had to be received on DVD-Rs that were routinely left unsupervised with untrusted intermediaries in very shady parts of the world. I suggested putting a message authentication code to ensure it hadn't been tampered with. The industry professional I was talking to would hear none of it, thinking the only way would be to transfer the entire contents of the disk over a very expensive satellite link to the head office and have it compared bit by bit. That MACs are a real thing that actually works, and that sending the data back and forth and comparing isn't actually secure unless a MAC is also used was like water off the goose.