Let's go technique by technique. Let's take kotegaeshi, which is a wrist control technique I learned in the context of Aikido, although my Aikido teacher, who is now deceased, was also a 2nd Dan in a Japanese karate style (I forget which one). Anyway, I KNOW that kotegaeshi works against a resisting opponent because I've used it. As I said, I once took a razor away from an emotionally disturbed man using kotegaeshi when I was working as a paramedic in NYC. I also performed the technique in non-training situations against many others (unarmed), and in training situations I have practiced it effectively with opponents who were definitely not making it easy. I will admit that certain big bulky types that weigh 220+ pounds and have wrists the size of small tree trunks are not likely to be taken hold of effectively by someone of my 170-pound slender body type. But the guy with the razor was bigger than I and the fact that he wasn't expecting it made it pretty easy. There is also the consideration that, with proper maneuvering/centerline technique, one can (as one should) take the opponent off-balance and also be able to use two hands against his one. I find kotegaeshi to be a very effective technique at taking a small weapon (pistol, knife, etc.) from an opponent while still allowing control of the opponent without inflicting serious harm. Obviously, you have to be up close to do it, and the situations where I would (unarmed) actually approach such a person rather than keep my distance are few. As I said, I've only taken a weapon from someone on the street once that way, and that was because it was a professional (paramedic) situation. In most cases I would probably keep (or increase) my distance or, if properly equipped and justifiably required, take a safer (for me) albeit less restrained approach, e.g., retreat, a whack to the armed hand with the nunchaku, or a bullet to the head, depending, of course, on the circumstances. But I dabbled in Aikido in large part for the same reason I started young with the nunchaku: I wanted to be able to disarm an opponent armed with a knife without killing him or her. Ah yes, that reminds me: I did take a pair of scissors away from an angry inebriated girlfriend some years back in Puerto Rico using kotegaeshi, but prehaps that was, as you say, candy from a baby. In any event, in my humble opinion, kotegaeshi works.