Years ago I was assigned to do a swimming pool refresher course for someone with well over 100 dives. She was about to take her annual dve vacation. She had all her own gear, and it was high end. It included a hose-connected AI computer. As she turned on her air, she noted that her computer had read the contents of the tank and determined it was EANx 32. When I told her that her tank had air, and the computer was just reading the nitrox setting she had put in previously, she refused to believe it. She insisted her air integrated computer always analyzed the contents of her tank. I told her the dive shop did not have the ability to make nitrox, and she finally believed me.
I remember when you posted this story a while back, and it's one of my favorites. Perfect combination of humor and cautionary tale (because no doubt there are plenty of divers like this among us.)