A vast hidden surveillance network, powered by the repo industry

The scan of the license plan is not really the issue, it's the collecting of the scan, tagging it with GPS, and aggregating the scan into large, permanent databases that can be accessed by both government and private corporations.

If all you do is scan a plate and display "car payments past due", or discard the scan if the car is not wanted, it's not all that different from a human looking for a car.

But these folks are creating historical databases that capture everywhere you have ever been. These sorts of databases can be mined retroactively to discover all sorts of sensitive information, similar to what was pointed out by Justice Sotomayor in the recent GPS tracking case, U.S. v. Jones:

"GPS monitoring generates a precise, comprehensive record of a person's public movements that reflects a wealth of detail about her familial, political, professional, religious, and sexual associations. See, e.g., People v. Weaver, 12 N. Y. 3d 433, 441-442, 909 N. E. 2d 1195, 1199 (2009) ("Disclosed in [GPS] data . . . will be trips the indisputably private nature of which takes little imagination to conjure: trips to the psychiatrist, the plastic surgeon, the abortion clinic, the AIDS treatment center, the strip club, the criminal defense attorney, the by-the-hour motel, the union meeting, the mosque, synagogue or church, the gay bar and on and on"). The Government can store such records and efficiently mine them for information years into the future."

While the government can currently look up your license plate information, or track you manually, they are limited by their resources. (From Alito's opinion in U.S. v. Jones: "But it is almost impossible to think of late- 18th-century situations that are analogous to what took place in this case. Is it possible to imagine a case in which a constable secreted himself somewhere in a coach and remained there for a period of time in order to monitor the movements of the coach's owner?") A nationwide database of historical location information -- that may not currently require a warrant under the 4th amendment to access -- is ripe for abuse. Letting private companies access the data is also scary.

These data brokers are probably right that they don't currently violate any privacy laws, however. But that just means we need to change the laws, as I think this most definitely needs to be a violation of privacy.

iamsalman offers a great response. Legally (and conceptually) there is the idea of a collection, a compilation being valuable in and on itself: this has been enforced to prevent people from selling phone books and TV programs without paying the original ‘compilers’, phone companies and TV stations, not as operators but original authors of an exhaustive description. Collecting changes useless information into, anecdotes, into a usable product: that’s the whole point of those companies, they (presumably by contract) guarantee a return rate that makes them economically sound; that changes the nature of ‘looking around’.

This idea is essential to all the creep factor around Google’s recurrent controversy: the problem is not taking street pictures, but guaranteeing that any house can be seen by anyone; it's not to murmur in your boss's ear ‘that’s the sub-commissioner in grey’ but potentially matching anyone’s face to their full public history. This is what made every page of a phone book precious, and every post-it with a phone number on it worthless.

It's interesting that in a software world the difference between good and bad systems can be a single bit, leave debug=true and accidentally record all your keystrokes, or your wifi packets, or store info permanently instead of temporarily.

How about a google glass like device, that we all wear all the time, and the camera runs all the time, and sends face pictures of people with the GPS coordinates and the timestamp?

This is all fun to talk about, but none of these is going to end well.

And unfortunately, the data brokers can even argue that the system includes an identity reset just like iOS - just request a new plate from your state...

However, this won't work, as linking the two records is trivial via DMV records...