It
Stop them.
The only advantage in waiting to actually catch them red handed is you will be able to add to your list of regrets, not stopping them when I told you to.
I like to say, there are only two types of trouble your children are in — the trouble you know about and the other kind.
If you don’t know what trouble they are in, then they and you are in a heap load of it.
I am not proposing buying your son a semi-automatic weapon so you know what he is up to. But I am proposing you figure out what your children are struggling with, because when it comes to children, ignorance is never bliss.
At least not for long.