What about the girls that want to go hang out in they boys’ locker rooms and bathrooms?
It is a bad idea no matter how you slice it or dice it.
It’s never an utterly risk free situation anywhere. The best we can do is mitigate the risks.
Boys teasing girls who choose to do that, are probably messing with bull dykes in the making (not just tomboys). What boy would want to get humiliated before his peers? They’d probably observe some kind of detente.