The other night, I had an interesting question put to me by one of my Brown Belts about a concern not being able to get out of a rear choke put on by one of her male friends. I said, "of course you couldn't because they already had the choke on, nor could've anybody else if on that tight." That’s similar to saying, ‘how do you stop a punch when it is only a centimetre away from your face?’ You are not supposed to let it get that far, you react the moment you perceive the threat (or at least see it coming). The same goes for the choke.
Self defence techniques are at their best when applied early. You don't let the opponent take away all your escape options. A technique’s effectiveness should not be judged solely on scenarios where your opponent is aware what's coming to them and they react accordingly, compromising the technique.
Many techniques are taught and practiced but not all are going to make it through the goal posts when it comes to the final crunch in a situation. But all techniques need to be practiced to ensure the understanding of reaction and body motion. A martial arts expert is a person who fully understands 'all' techniques and they are in a pretty good position to say what is or isn’t effective. Sometimes techniques may seem fruitless or even trivial but we are in the business of examining all options.
Techniques are only as good as the person practicing them. Not all of them are going to be good for everybody in every situation. That's why there are options.