709
An LAPD helicopter claimed to have ID'ed protesters from above and threatened to "come to your house"
(www.motherjones.com)
This is a most excellent place for technology news and articles.
Gyro/accelerometer data isn't accurate enough to do that. Small errors in the data add up and will quickly drift away from the actual location. You can use it for video game controllers, but not tracking over large distances. Edit: there's a reason the best VR tracking often uses external methods, not controllers alone.
But most phones have GPS and that's where the real problem is.
That gives me a good idea. A week before the protest buy burners, use them frequently near republican supporters' house, go to a protest, use your phone all the time in the protest, dump them near the police, let them enjoy the fruits of the regime they supported.
Gotta clean and sterilize them.
Diabolical. In theory, of course. Definitely just in theory.