I never heard of shared lockers when I was in school. A high school I saw video from has shared lockers. Two sisters shared lockers. After the older one graduated, the younger one shared her locker with a friend. How common or rare is it for schools to make students share lockers?
Don't know how common it is now, but I had a hall locker in 7th through 12th grade. Shared them every year. Had gym lockers those same years. Did not share them. 32-04-14 was the combination for my gym locker's padlock. And to think: I haven't used it since this afternoon at Planet Fitness