I see that Magenta8 but at the same time, if there is somebody with you who’s a danger to you, tapping umpteen people on the arm and showing them a secret gesture which they may well not know anyway isn’t going to get you anywhere is it?
I would have thought that pressing the palms together in a praying attitude 🙏 would have been a more sensible universal sign for help.
I think the whole point is that you signal your distress without alerting the person you are with. If you pressed your palms together it would be too obvious.
I have just watched a short film where a woman, accompanied by a man, touches the arm of passers by and then displays an open palm which she then closes. This apparently is the universal sign for "Help!" Anyone witnessing this should approach the person and ask if they need help. I am posting this because I think it should be more widely known. Please pass it on.