That said, I hear stories like yours (from friends) and it always baffles me because that's just now how our family operates. I have a downtime pin on devices for the same reason I lock the door to my car even though it's like 50% breakable glass windows.
My kids know the rules. One of them for sure knows the pin. But they also know that if they use the device outside of our agreed upon guidelines, they're in trouble.
I'm sincere in asking, aren't behavior controls a lot better than technological ones?