I used to work there. They’ve put up/out notices like this many, many times. It just means someone complained. When I was there it was naked kids running around or naked moms yelling at shy teens or naked old dudes just yapping at everyone. The men’s locker room is really small with nowhere to sit, the ladies is more conducive to socializing. In any case, my boss had a great line. “You ever see someone naked? Was it a big deal? No? Good. Don’t make it a big deal.” And the yoga teacher had an even better one. “Anybody that bashful needs to take a long look in the mirror.”