Rupert Atkinson

At one extreme - one of my first instructors insisted that anyone who got a shodan in any style must wear his black belt when training - even not an Aikido BB. At the other, I have seen Aikido BBs told they need to regrade when joining a new style. I have also seen senior grades tell junior grades they are not worth their BBs even within their own style. In the UK there were various associations of marital arts that would accept anyone - so lots of hyper inflated grades. At the end of the day - grading is just hierarchical BS. If you are good at something, others will look for and notice skill and say, 'teach me'. If you have a BB cert, others will 'assume' you have skill and say, 'teach me', and often, they have no skill. The BB cert blinds some people. And sometimes they have a BB cert but little skill, so bad that everyone notices it. There are all sorts out there. Then as in this thread - some BBs rescinded for various reasons - some good ... some bad. An org can and will do whatever it wants. If the church kicks out a priest he is no longer a priest. If the police kick out a cop, he is no longer a cop. If a teacher is sacked for bad behaviour etc., he is no longer a teacher. He may still have the knowledge, but he can't teach. But they are big orgs. Aikido orgs are small - so it's all word of mouth. If you are out you are out - for better or for worse. If you don't let the kid with the ball in the team, there will be no game. It's all just human relations. If you find yourself out in the cold ... join a new org and show them your skill. If you have skill ... no problemo. Orgs will always be suspicious of new members if they claim high grades since grades = power in orgs.
Me - 2nd Dan for 27 years. When I had a club in Korea we had many visitors. Anytime there was someone of a higher grade - I let them teach, no matter the style. My first teacher was right!