A warning that automated license-plate cameras are spreading across US streets and quietly tracking everyday Americans, framed as bad news for privacy and Fourth Amendment rights.

• Flock cameras are mounted on street corners nationwide, scanning and logging cars and movements in the name of public safety.
• Most Americans have no idea these cameras exist or what data they collect.
• Critics say the network amounts to mass surveillance of ordinary people who committed no crime.
• People who oppose the cameras — even just by posting online or removing them — risk being branded domestic terrorists.
• Connor Boyack of the Libertas Institute, which focuses on Fourth Amendment rights, has tracked the rollout for years.

Outlook: Expect the camera network to keep expanding, with privacy and free-speech fights intensifying over who is watching and how the data is used.