Wasn't saying arrest, I mean pre warning/monitoring. If you run a shop you'd get an alert saying watch your fours.
So the police should set up a Flock network for teenage boys or what?
I have no idea what Flock is, last I knew it was a web browser designed for social media which failed.
You must've been living under a rock. Flock is the panopticon camera network in the USA. It watches most people's location most of the time, so the police can just type in someone's identifier and find out where they are and where they've been.