If you are ignorant that your techniques won't work, but full of confidence that they will, surely you will still give off the same level of confident body language, whether it will actually work or not. And therefore for intimidation it will work the same way, and you will only become unstuck when it develops beyond mere intimidation. Obviously false confidence is a dangerous thing, and could lead you into all sorts of trouble, but acting confidently, even if you know you cant back it up has got to be better than not.
Also having tested your skills are you then more or less likely to try and use them? Maybe this is why takeda said of aiki 'the secret of Aiki is to overpower your opponent at a glance and to win without fighting' mind you, doesnt work on taxi drivers