When I was in Catholic school the girls had to wear skirts and knee-high socks. The hem of the skirt had to touch the ground when kneeling. Some girls would roll their waste bands to make their skirts shorter. The nuns would often make random skirt checks if they thought the hem was too short. Violators were given detention.
Some of the younger guys at the gym have started wearing knee-high black socks. Add in a pair of below-the-knee black baggy workout pants and the guys look like the Catholic grade school girls from my youth. I find this trend rather odd.