It was actually SGM Parker that started Mr. Pick on the blade. He just appeared to have pursued it more than others, and worked with the SGM to that affect.
Also, formal training with the blade does not begin until 3rd black or so - but that's third black in time duration and mastery of the basics as he teaches them, not stripes on the belt. We all get exposed to it at white, and in fact there are particular lessons of alignment I have taught using a blade on someone's first lesson. But to understand his knife work, you have to understand his empty handed kenpo. And that takes a long time, regardless of where you're coming from. So, the elements of the blade work are founded in the constructs in which he teaches and operates his kenpo, so to "learn a knife technique" one is missing the boat. The constructs used in his kenpo are principle-based and not used in other cirriculum's, including Ed Parker's. Those are what begin at white belt, and they must be absolutely sound (6-10 years, IMHO) in order to really bring the knife in battery effectively
Hope that clarifies.
Cheers,
Steven Brown
UKF