Hey Knovice,
At the time of the video, 1986, passing, trapping, locking and stripping was THE WAY amongst SoCal FMA guys for dealing with a knife. As I mentioned before I was dealing with the "Big Secret" problem for showing certain techniques. This is why you see sections on passing, controlling and muscle strikes without the complete disarms and then some of the more rigid, single move disarms.
I still believe these control to a lock to a strip moves can be effective, in the right situation. However, the strip portion of almost all of the moves involves some type of contact with the knife, 90% of the time with the blade. FMA stylists will tell you they hit the back of the blade or the flats or that the hand is locked in place before the strip, preventing you from getting cut. We were using life size aluminum training blades, even back in the 80's, and we really believed this.
As we started working these moves with live blades of various shapes and styles (Very Slowly!) We found that those pesky edges seemed to contact your flesh a lot more than we thought. We had trained in numerous disarms that had you removing the knife from the BG's hand and using it against him. This often involved some awkward grips on the BG's knife, but it looks so coooll! When we substituted live blades again, you suddenly found that about half the time one or more of your fingers ended up on the razor sharp edge of the BG's knife. Another indicator to re-evaluate was that hardly anyone did a successfull lock and strip in sparring.
The current technique that I teach as a primary defense, and that is taught at our state police academy, is a variation on the Kali/Silat dive entry. To understand this, picture a BG throwing a straight right punch at your chin. You bring both hands and arms up like you are about to dive into a pool, hands together, elbows out a little and head tucked, using the arms for cover. The punch would deflect off your left arm and the hands snapping out, combined with a brisk step in, would strike to the face, throat or maybe a shoulder stop, depending on the situation. The key here is to combine the step in and arm movement for a deep drive, that snaps the head back.
To change this into a knife defense you just change the arm position a little. If the knife is coming down or in on an FMA angle 1 (high right, coming down) the left arm drifts out enough to deflect the arm coming down and the right hand goes to the face. Your drive should snap the head back, maybe even knock the BG on his butt. If you picure 100% of your energy going forward, maybe 15% goes into the deflection and 85% to the BG's head. The strike is an open palm strike and when you make contact your fingers are attempting to gouge/scratch eyes and do other damage also. In training with attackers in FIST and Redman suits, if you do the initial strike right, the knife doesn't get to the intended target or doesn't have enough energy to do much damage. If it's a highline backhand, you go to the outside and over the arm, with the right deflecting and left striking. If it's lowline slashes, you drop the deflecting arm the necessary amount. If it's a straight thrust you sidestep and deflect with the appropriate arm. There are simple follow ups that work from all of these positions, but it's the intitial power shot to the face/head that makes everything else work.
This is being taught to LEO's in my state as a universal defense for any agressive attack. If the BG whips his hand out from behind his back and towards my body, I don't have to try and see if he has a knife, empty hands or even a pistol. I deflect the approaching arm, while simultaneously smashing the head and follow up appropriately.
I have used it twice on the street, once against a straight empty hand punch and once again an angle 1 beer bottle attack. Both times it dumped the BG on his butt in a daze and follow up was easy.