Enchanis books were on sale in the mags in martial arts stores,everywhere and anywhere.
I bought all of his books through O'Hara Publications and there were no questions as to who I was, or what I did for a living.
( restricted book,lol,a sales hype more like it )
There was nothing secretive in the book,it was actually an exaggerated use of the knife for combat purposes.
Like Jo Bong Lee's sword usage ,Enchanis knife was too much ,a show over true usage.
Enchanis was Never a Green Beret.
The Course he ran was not just for Green Berets,it was an open class to all interested.
Here is part of a story from an attendee of the class:
"My fondest recollection was of day 1. This class was open to everyone and not only Special Forces soldiers. There were many in attendance. Mike gave us a synopsis of what the class would entail and proceeded to 'personally' demonstrate to each and every participant that the techniques were very real. Green Berets, as well as the others, were tossed around like rag dolls. The pain he could inflict was surreal. He could hurt someone badly with a finger. On the second day there were only SF soldiers there to continue the class. He seemed to revell in this by stating that only the "real" soldiers had returned."
No Secrets,No Restrictions,No Green Beret specific training.