Pervasive automated license plate scanning is a qualitative change. It&#x27;s one thing to have a chap by the side of the road writing numbers into a piece of paper; it&#x27;s another thing entirely to track most of the routes of all vehicles in a city. You can&#x27;t trivially extend the principle of one to permitting the other, since it&#x27;s not feasible to flood an entire city with spotters with notepads.