It is honestly just a terrible idea - you are essentially placing a target on yourself, no matter how you use it. Simply scanning a crowd of people with a camera, you are identifying people protesting from other civilians, in real-time and no cost. If you watched a crowd from above, over time you could find all sorts of patterns. In some countries, that could mean your whole family disappears.

The only groups I see benefitting from this are the agents of oppressive regimes, and the meth heads breaking into your storage shed at night and stealing your bike.