Our gym/dojo is a hybrid of Muay Thai, BJJ, and Kickboxing. We implemented a system to understand the importance of seniority and discipline when it comes to age and ranking, so we use colored prajiads to categorize experience and the expansion of their lessons throughout the years, a sixteen year old with a green prajiad is a senior to a twenty-five year old man with a white one. It works the same way as belts, as with promotion tests and such, but it doesn't take away the validity of our location. Also because classes are split on a schedule where an hour is dedicated to separate martial arts and such, and it was easier to keep track of members by their bands and belts, because some did both martial arts and some did not. And for formalities, I'm sure it changes from place to place but our location has a very sacred ritual in means of promotions of rank and stuff. But yes, my point is, some schools and gyms use it for different reasons and if they do, it doesn't remove the validation of their place.