Toll transponders fitted as standard

I think some time in the future car registration will include a transponder for automatic tolls rather than just number plates and a sticker. Standards are good, but drivers need to be able to turn off their toll boxes if they're not using toll roads, for basic privacy, and that option (plus the fact that it's hard to check for a transponder visually) means the standard benefits evaporate.

Anyway, my main point is that transponders on every car is a situation begging to be misused by both law enforcement and criminals. Once most (or all) cars are fitted with toll transponders, police cars can be fitted with devices to read all the signals around them and check back with a database of stolen cars. Before long, that mission creeps wider to include any speeding fines, parking tickets or out of date registration payments. Citizens who keep getting pulled over for database errors then demand the ability to turn off their transponders. Turning off the transponder is soon seen as a signal that you have something to hide, and therefore must be guilty.

On the other side of the fence, petty toll dodgers have incentive to produce and fit boxes whose identification changes randomly every minute, so that they never get a toll bill. Pranksters get incentives to change your ID to a known stolen car, or to change their own ID and speed through a red light so you get the ticket (this has already happened with home-printed number plates). Car thieves need to change the ID before the car can be sold, but it's more likely they'll just rip out the box and ditch it. It's not quite as dystopian as I was hoping to make my point, but it's not a clean idea either.

Mokalus of Borg

PS - As too often is the case, this is a grey zone.
PPS - Those kinds of things muddy everything up.