Law enforcement agencies across the U.S. are systematically using Flock Safety’s automated license plate reader (ALPR) network to surveil political protests. An analysis of 10 months of search data, obtained via public records requests, reveals that over 50 federal, state, and local agencies ran hundreds of searches related to protest activity. Police often use vague search reasons like “protest” to query a massive, shared database of vehicle movements, effectively creating a permanent record of who attends demonstrations. This surveillance dragnet targets a wide spectrum of groups, from large-scale “No Kings” rallies to specific organizations like Direct Action Everywhere. By collecting data on every passing car, these systems turn a tool marketed for fighting crime into an apparatus for monitoring constitutionally protected speech and assembly, creating a significant chilling effect on dissent.