Just get a separate classroom for those women who care about being watched. There isn't any strong alternative, is there? Nobody can give a fair and concrete rule on what constitutes a bad stare. And it seems to me that women generally will choose tight yoga clothes over being watched(at least around where I live.) You can't blindfold the others unless you're some kind of a dictator of a totalitarian regime. So what can we do, except segregating those who are uncomfortable being watched?
Then there are also issues with gay men staring at other men and all that third sex stuff... but these other cases aren't posing as much of a problem because we don't hype over them.
Maybe we should learn from these third sex cases?