I grew up with a pretty strict cultural/religious background, which meant that lots of vices were off the table while my siblings and I were coming up.
There was no going out to party, no drinking, no drugs, no smoking (which didn't stop me), no dating boys or girls, and no inconveniencing other families with your presence by overstaying your welcome at someone else's house.
As my siblings and I got older, and our parents saw that we were semi-capable of taking care of ourselves, they seemed to care less and less about their religious rulings and didn't pretend like their lives were over because they discovered one of their kids was into smoking pot or had the occasional boozy night out.
But there's one rule in my family that can never be broken, and it's that snitching will never, ever, EVER be tolerated. By child or adult.
I remember my mother, the sweetest woman in the world, getting the coldest, most callous look in her eyes when I told her I was thinking of telling the teacher that this one kid had done some base, elementary school nonsense. She made it very clear to me that I'd be doing no such thing.