That’s what I said, they do that now with a phone. And generally, in my experience having kids on school sports teams, smart phones are banned in changing areas. At least the ones the coaches at our school oversaw. I can’t speak for all of the schools.Right, because nobody can easily do that now in a locker room with a phone?
And that's not even the worst of it ... there are already spy cameras in all manner of objects that someone can take into a locker room concealed if they want to do this.
As the Dani Mathers case proves, there are laws to prosecute those who would do what you suggest some people may. So, no they're not going to ban people who legitimately wear glasses, because Spectacles exist.
Just like everywhere else on the Earth, everyone needs to exercise personal responsibility to know their surroundings in common public spaces, even in their own homes, and when the unthinkable happens, the law will punish those who have violated your privacy, regardless of where it occurs -- that is the deterrent -- not banning legitimate eyeglasses.
As for the ban on all glasses due to people someday having designer glasses with cameras in them, well that’s a concern I have due to people tending to overreact and failing to see nuanced differences when formulating bans. Like the jurisdictions that ban all cell phone use in the auto, even when your phone is acting as a GPS and calling turn by turn directions to you.