A few years ago I was a police officer and Chief of Police for my hometown. One of the technologies that was just hitting the market were the 'automatic license plate scanners'.
At the time, they were 'advertised' to the police department as a device that would make finding vehicles with plates and insurance out of date and compliance. Also, if the person registered to the vehicle had a warrant that would also throw up a red flag. This was suppose to be a device that would help 'clean up the streets' so to speak. It was a costly device so that only the large departments could even consider fielding one so I didn't give it another thought.
But another use has apparently been used with it. With just a few more settings the police can now RECORD ALL license plates with a time-stamp of where they were at when they were recorded. By doing this they could build a database of your movements. 'But I don't do anything wrong, so what do I care what they do'. That is what a lot of people say being apathetic to this kind of thing. Here is the problem though, with the amount of laws and regulations that we have on the books,(not to mention how simple it seems to be for the government to consider you a 'suspect' for something) its only a matter of time before you break one. Then they can go back in this massive data base, look at your movements etc, and see what else you might have done.
Is this right? No, its not. It's a violation of your 4th Amendment rights. Is this happening? It appears to be. I googled a simple phrase, 'cities using license plate scanners to store information' and the first page is nothing but articles about various major cities DOING this.
The one thing that this proves is that you can take ANY new technology that at the time had a benign and non threatening use, and turn it into something completely different.
There is the quote from Lord Action, a British historian of the late eighteenth and early nineteenth centuries, in a letter to Bishop Mandell Creighton in 1887:
"Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men."
This seems to be true and is unfolding before our very eyes. So all I can say to anyone is be careful of the power you give to any political or government entity as history has proven time and again.