It's the database query, not the physical cameras. In the pre-digital age where privacy was considered in constitutional law, tracking people's and vehicle's movements was horrendously expensive - you'd need multiple detectives doing things by hand per person of interest. This meant that it was reserved for when the government already had pretty strong reason to believe in some sort of wrongdoing. Even with a personal, non-internet-connected doorbell camera, the police would need to identify what cameras exist for a location and contact the owners in order for the footage to do anything.
With automated license plate readers, they can simply collect everything with a reasonably affordable network of cameras, then query the database when they want to find a particular pattern of activity. The police have already detained people for frequent border-crossing between marijuana-legal and illegal states. This gets exacerbated by granularity and extensiveness - imagine an anti-choice state pointing cameras at every maternity care parking lot in the state and tracking who visits them for cross-referencing with visits to pro-choice states.
And with the existence of parallel construction, there's no reasonable way short of dismantling the ALPR system to avoid abuse against the citizenry.
With automated license plate readers, they can simply collect everything with a reasonably affordable network of cameras, then query the database when they want to find a particular pattern of activity. The police have already detained people for frequent border-crossing between marijuana-legal and illegal states. This gets exacerbated by granularity and extensiveness - imagine an anti-choice state pointing cameras at every maternity care parking lot in the state and tracking who visits them for cross-referencing with visits to pro-choice states.
And with the existence of parallel construction, there's no reasonable way short of dismantling the ALPR system to avoid abuse against the citizenry.