I once saw an interview with a guy that designed garbage cans for National Parks. When asked what the hardest part of the job was he said, “accounting for the considerable overlap between the dumbest humans and the smartest bears”.
For months after some researchers “proved” our code signing system sound I was still finding security holes in the system. To this day I’m not sure what they proved. That the architecture worked? We’d already proven that to a hundred people.