I've not met any of them, but I have trained at 2 Tai Kai (seminars/conventions taught by Hatsumi Sensei) with Hatsumi Sensei, one in 2002 and one in 1999. Stephen Hayes was attending the 1999 Tai Kai. The head of the dojo I train at is a personal student of Hatsumi Sensei (as all shidoshi are) and was once a student of Hayes.
