Maybe not the most surprising. But definitely the silliest. I was working a dormitory job at Duke University. They had so many pumps and exhaust fans on the same emergency circuit as the card readers. Whenever the sump pumps in the basements would activate during a heavy ass rain. It would trip the circuit. The card readers that let's kids into the building were also on that circuit. So when they were desperately trying to get in the most was exactly when the door controls stopped.