Don't be misled by the title of this Youtube video. Most of the techniques in this video are not "illegal", however they are frowned upon in certain jurisdictions, and are misunderstood by juries and/or judges. Most of these techniques have been around since well before WW2, and some go back even further than that.
Now while the techniques are valid, the AI used in the making of this video is execrable to say the least. The voice-over is fine and does a good job of describing the techniques. However a great deal of the visual portions are just worthless.
All that aside, as I said in the beginning, the techniques themselves are real and I was shown quite a few of them by my former instructor Carl Cestari. Oh, and some of them are not lethal, but can cause serious damage. As with other videos I've shown before if you unfortunately find yourself in a serious situation, you had better be able to articulate why you felt it necessary to use one of these techniques, and have a good lawyer.
