Did you forget Murphy's Law? If it is possible for the data to be used in a malicious manner, someone will eventually use them with ill intent.

The key to preventing abuse is to make it more difficult by several orders of magnitude than allowable uses. One way to do this is to only store plate scan records where there is a pre-existing reason to track the location of the vehicle, and purge those records once that reason is no longer valid.

You can't search what is not stored.