According to the news there is already an issue in Hong Kong in gyms where people's cell phones are being used to take pictures which are subsequently posted to the internet.
This is especially interesting since the article ends with the comment that the Chinese are less concerned about privacy issues than Americans, for example.
I haven't heard of cell phones being banned from gym locker rooms over here, but I would certainly understand. I wouldn't want naked pictures of me on the internet. At least not till I've lost all my weight! 😉