What really surprises me is that so many Reality/Combatives boys give so much credence to the claim that Sayoc was this real-world combatives knife system.
That's not surprising to me. As with anything, the person who comes up with the best maketing for a concept, preferably before others, usually is seen as a top authority.
I've not seen anything of their system aside from the movie "The Hunted," so I'm writing about the concept in general, not this system specifically.
I've seen some of the most popular knife and videos, past and present, and IMO a few of them were either bad or just OK.
There have been several threads on the top "gurus" on combat/defense psychology, a topic that has been relatively ignored for decades. People like Grossman and Siddle are for the most part the only ones who wrote best-sellers on the subject, so they would be big names an authorities no matter what the content of their books.
I just finished the popular "must read" book so many people are raving about, the "Gift of Fear." There is some info useful to people who never studied or trained in awareness, but IMO the book is just a lot of padding and possibly a subtle ad for his business, and the useful info could be given on one page. I'm pretty sure this is the book Jerry Van Cook was referring to in "Real World Self-Defense" as being mostly worthless but the useful info could be described very quickly, which he then did in his book. Even so, I've heard and seen lots of people in RBSD and martial arts highly recommend this book.