Indeed, that's unfeasible. But if you start reasoning like that the best way to prevent children from sexual abuse is to simply not have children at all. After all some of them will surely be victims at some point.

I'm not a big fan of the nanny state, I think life is full of risks and if you arrange society in such a way that all the risks are gone you will squeeze the life out of it as well. It's a hard balance to get right but I feel that going overboard on the protective side is not the answer.