... It knows where I am. It knows how fast I'm going. ...
Well, maybe, and maybe not.
I recall a couple years ago, when I was traveling south on a street in a nearby town, but when I glanced at the GPS gadget, it showed me about a block north of where I was -- and headed north. Traffic was light, so I looked at it frequently, to see what it did, and it showed me continuing north, until my actual location was nearly a mile south of what it showed. Then it decided I'd made a U-turn, and was proceeding south at a rather high speed. Finally, the little You-Are-Here icon reached my actual position, and slowed down to match me. A bit later, I checked its records of that trip, and it showed a max speed somewhat over 250 mph.
So if the police had access to that data, I'd have got a ticket for going about 8 times the legal speed limit. I sorta suspect that most judges would laugh and toss it out. But if it'd been only twice the speed limit, I'd probably have had a large fine to pay.
And note that the position was credible, though it was roughly a mile off. A couple of months ago, however, I noticed that, while my bearing and speed seemed accurate, my GPS position was roughly 100 miles SE of my actual position, which put me maybe 10 or 20 miles east of Cape Cod, driving along in the ocean. It stayed that way for at least 15 minutes, and then suddenly popped over to a local street a few blocks from my actual position.
I've also seen it showing my position as being in north-central Canada, and somewhere in Nevada, when I was actually in the Boston metro area.
So if the police are tracking our GPS position and speed, we have no defense. Yes, maybe the judges will dismiss the tickets that are obviously so badly wrong. But if they're only off by a few miles or mph, we'll all be getting completely bogus tickets that we'll have to pay.
Of course, they may still dismiss them for people who "look right" and "talk right", as they do with claimed drug offenses. ;-)