For reference, and to cross-link: this matches Idea - Turning the weapon around, raising awareness!
(the idea in that post - which has aged a bit already - is to make this into a strategical campaigning power tool. Note that no App is really needed, because anyone can do it already, as @anon51879794 already stated above, but the app would increase the power, like a ‘bump stock’ on a semi-automatic gun, if you will)