Trust me, he did you a favor.
I really don't know. Don't get me wrong, the Gracie Jiu Jutsu system is formidable, and I am not knocking it at all.
I think that in many ways the Gracie Family have created a style of martial art that was perhaps more inline with what Prof Jigoro Kano originally set out to create before Prof Kano realised his arts potential as an international sport.
I think that Gracie Jiu Jitsu is more attractive to a greater number of the public in our modern time because it is more applicable to self defence than competition Judo is, at least as Judo is taught.
I am not a Jeet Kune Do expert, but have read my fair share to understand the differences between MMA and self defence, and think that the areas that Jeet Kune Do stylists shine can often be the areas that are illegal in MMA, Judo and BJJ, in the same way that people who subscribe to modern versions of ninjutsu would likely fare better outside of the MMA ring than inside it.
I vaguely remember the book, and also have a fair amount of history applying locks/chokes including traditional locks that aren't allowed in BJJ, such as those found in aikido that a lot of people rule out as ineffective rubbish.
However, I think that if someone skilled at the aikido techniques who also was experienced in BJJ and Judo were to apply some of the aikido techniques with force and speed, they would, in much the same way that the locking techniques that are legal, if applied with too much force while not taking notice of your partners "tap out" responses, could do as much damage as many of the locks that are associated with Judo and BJJ.
Now, don't get me wrong, I am not suggesting that people train like this.
But I am just suggesting that some of the techniques that have been ruled out as rubbish due to the way other people train, or that are too dangerous to train with in rolling / randori due to how hard some of these techniques are to apply with control without damaging ones partner, i am suggesting that some of these banned techniques would work if used with excessive force.
I mean, even the Wally Jay finger locks, if applied swiftly, with great force, while your partner is un-expecting,
would likely do serious damage to one or more fingers and wouldn't take that much skill.
If they were applied with quick precise force, rather than in the way that Professor Wally Jay demonstrates the technique, in a way to make them appear much like many of the aikido techniques that result in the passive training partner having to throw themselves in order to escape from having their joints popped.
Personally, if i were to practice the self defence side of Gracie Jiu Jitsu (or any other quality self defence system), i would include such damaging grip breaking techniques as part of the game.
Sure, its not as nurturing in philosophy with regards to the destructive nature of such techniques,
however, i think that in some rare circumstances you need a way to cause damage quick, as you may not have the luxury to roll for excessive amounts of time on the floor before you wear out your physically bigger attacker before you tire him out so you can then tap him out...