ya, (correct me if im wrong guys) but traditional JJ/BJJ scholls will only allow brown and black belts to go for certain subs below the waist. white belt is rrstricted to above the belt only.
i thought it was weird too, i mean i know how to do knee and ankle locks, calf slicers and what not. but i guess the idea/theory is since white belts are still learning, they need to learn proper control during below the belt subs since theres gigher risk of severely injuring someone and their life temporarily by crippling them for a short timem cause some people go full strength right away even when sparring. i secure the position and gradually increase pressure since everyones range of motion is different.