I wonder if crowds in a chaotic situation (e.g. a riot) can be made more smarter, if everyone had a visual/sound signalling system.

E.g. A RGB colour glow wand or disk with set of predefined buttons, that is clothing mountable.

With the right set of rules, you could provide tactical information about a kettling in progress etc... (e.g. Lots of people pressing red lights, thus showing a sea of red along the line of conflict)

It could also be tied to a radio system, that could vibrate based on the number of colours it receives from nearby participants.

pros: No smartphones needed. Real time visual feedback to everyone else.

cons: No privacy of communication. You hold the wand, you get arrested.
-- mofosyne, Mar 07 2016

random, halfbakery