From the Electronic Frontier Foundation:

Do you drive a car in the greater Los Angeles Metropolitan area? According to the L.A. Police Department and L.A. Sheriff’s Department, your car is part of a vast criminal investigation.

The agencies took a novel approach in the briefs they filed in EFF and the ACLU of Southern California’s California Public Records Act lawsuit seeking a week’s worth of Automatic License Plate Reader (ALPR) data. They have argued that “All [license plate] data is investigatory.” The fact that it may never be associated with a specific crime doesn’t matter.

This argument is completely counter to our criminal justice system, in which we assume law enforcement will not conduct an investigation unless there are some indicia of criminal activity. In fact, the Fourth Amendment was added to the U.S. Constitution exactly to prevent law enforcement from conducting mass, suspicionless investigations under “general warrants” that targeted no specific person or place and never expired.

More at the link. I’m a donor to the EFF as they protect bloggers’ rights.

BTW, license plate readers/cameras are illegal in New Hampshire. Alas, they’re not, in Vermont.