Loveparty…
I am not naive and was a teenager once too, I know exactly what goes on. The problem is some “genius” is going to say, Have a Shiur for the boys or have a place the girls can do chessed, Like that is going to work.
I know people who let teenagers hang out at their house, they figure its better for them to hang out (in mixed company) in a place where they can be watched and in a safe place than a place where nobody is watching and who knows what goes on.