But, as long as he does not try to commercially pass off his 'art' as genuinely rooted in Ninjitsu and does not attempt to teach it as such to anyone but his sons, then, other than them, who does he hurt?
His kids, potentially. Anyone they pick up and try to teach, 20 years down the road when they feel qualified to teach their secret family art for money.
Let me ask you somthing Suk...
How would you feel if I joined a LARP group and pulled out my foam fantasy sword for a while, then came on here and told you I was starting my own Koryu Sword School.
At the very least you would find it, stupid, that I would misuse the terminology so badly, knowing that it couldnt be Koryu... but even beyond that, wouldn't it kinda burn your, ah, fish and chips, even a little after you put in the time and effort to learn, that someone could just claim mastership and teaching rights over what you do from some backyard play?
Thats one why I have so little respect for guys like Tew.