Some ultra-lefty must have come up with this after a heavy drinking session with his deluded mates in Pyongyang.
Nothing smaller than a ScanEagle will be effective in this role, and they are remarkably easy to jam with off the shelf technology. For anything bigger, you need an AOC and $millions X multiple, or some kind of expensive lease agreement.
Not going to happen.
With regard to shooting them down; after the first half a dozen are destroyed the police will put it on the back-burner (police presence in most of these areas is already overstretched) and the lefties will run out of donations. Game over.