I have a black belt in Danzan Ryu Jujitsu...
If I walked into your TKD school and wanted to be a black belt there on day one.... How would that go?
If I walked into your BJJ school and wanted to be a black belt there on day one... How would that go?
I trained Kenkojuku style Shotokan Karate for 15 years and made it to brown belt. If I go to any new Karate school, I would go as a white belt. In fact, if I go to any school out side of the organization that gave me a black belt... I would go in as a white belt. If I go into a Danzan Ryu school, within a different organization.... I would go as a white belt. To me, its a matter of respect.... if I have never trained in another school, organization or art.... why should I then consider myself to hold any rank in that art? If I can go into an art, that I have never trained, as a black belt, why would I want to train there, what do I expect to learn there? I carry a white belt in my Gi bag, for when I participate with other schools and or other arts.