Where a child spends time is a parent's choice. Who a child spends time with is a parent's choice. What a child spends time doing is a parent's choice.
If those things aren't true, then I don't know what the hell a parent is. I don't know the difference between adult and child.
I get that you have to strike a balance to not totally suffocate a child, but I don't understand just saying fuck it because something somewhere will slip through the parental filter. Again, reduction, not elimination. A parent can absolutely require that friends come over instead of their child go out. Especially if there aren't shared values and understanding between all the parents.