I've just caught up here-- it took me three hours of reading in this thread, with links! But I would like to respond, as a mother of boys in sports, that my children's schools didn't even utilize the shower facilities. They just didn't. And school PE classes were coed, and they didn't use them then either.
So, even though baseball was the sport-- I will state that my young men, who are now in their mid to late twenties, had NO occasion to even shower with their teammates. They brought their stinky selves home.
mo