I've seen some systems, like my beloved Modern Arnis has belts. However most of the other FMA I've trained were very informal. As a matter of fact much of the time we are in street clothes and are training in yards and parks. That being said, most of the people I've been training with over the years used 2 ranks...instructors and senior instructor. Everyone else is a associate practitioner. It has been a long time but I want to earn an official instructor rank in Arnis but as of now I am a High Green belt. With Sifu Vunak I am a full instructor in his Kali. I do not really have the need for another black belt but I am curious why people need the lofty ranks in a genre that 50 years ago didnt even have a belt system. Either way I look up and send my respect to all my seniors from the FMA genre.