I have never liked parties so I wouldn’t know. I also have never seen a flyer for a party.
If I had kids, I would tell them when they are old enough to have sex, they have to move out.
Of course you haven’t seen flyers for parties.
That’s my point, the parents have no idea about “parties like that”, because the kids are spontaneous, and always on the lookout for the home where parents aren’t there.
Since the kids aren’t going to acknowledge they are having sex or contemplating sex, you’d be throwing them out at about age 14.