Well, let's start with me! I was personally turned away from a koryu kenjutsu school in Europe back in 2001 or thereabouts. They were very polite and said they had to ask the headmaster in Japan. They eventually got back to me and told me politely but firmly "No". I didn't have any tattoos, didn't have a criminal record, no drug use, no links to Al-Qaeda, nothing like that. They politely told me my application was declined and I would have to give up Ninjutsu if I wanted to reapply.In addition, I know of quite a senior Shidoshi in England who was turned away from the Toda Ha Buko Ryu. He went to Japan in person to apply, but was still refused. He was also not accepted by the Araki Ryu. It may or may not have been Ellis Amdur's teacher that he asked. I can't say for sure.Then there was a Bujinkan person in the USA I know of. He tried to enter the Yagyu Ryu Kenjutsu under Meik Skoss in the USA. He was told no.I also have heard (but I am willing to be corrected as it is 2nd hand) that Master Otake of Tenshin Shoden Katori Shinto Ryu will not accept students with a X-kan background.Now maybe these are all isolated instances and not representative of the wider koryu teachers. I cannot say for sure.You've already admitted over on MAP you've never trained in a Koryu. Yet you keep making statements like the above.
How many instances do you know of a student being turned away from Koryu training based solely on the fact that he was a member of the Bujinkan.