SC Public Interest Foundation v. SLED Brief: Auto-License Plate Reader Database Endangers SCs' Privacy and Security

Matthew Cavedon

If you’ve driven in the Palmetto State, chances are the government watched you do it. The South Carolina Law Enforcement Division (SLED) oversees a vast network of automatic license plate readers (ALPRs) throughout the state. SLED’s ALPR database is not a modest record-keeping tool but a comprehensive statewide surveillance. As of early 2025, this system was capturing nearly 150 million observations a year—99.8 percent have no connection to criminal activity.

SLED decides which agencies or officers may access it, on what terms searches may be conducted, and how long data is retained. Once given access, a user can search any full or partial license plate number and instantly retrieve a detailed location history of that vehicle—including the date, time, and place of every ALPR capture—potentially exposing sensitive information about a person’s religious beliefs, political affiliations, or medical care. What’s more, officers need not meet any evidentiary threshold before running a search.

The Appellants filed suit alleging that the Legislature’s broad delegation of power to SLED to collect records of people’s movements—and retain them for future review and inspection—violates the separation of powers, nondelegation doctrine, and South Carolina Administrative Procedures Act. However, the circuit court ruled in favor of SLED.

Cato filed an amicus brief urging the South Carolina Court of Appeals to reverse that decision. Surveillance technology does not stay within the boundaries its operators initially envision. Systems justified as tools for solving serious crimes end up being abused for routine enforcement, political monitoring—even personal vendettas. The history of law enforcement’s use of database technology is one of mission creep and misuse, enabled not only by bad actors but by the absence of meaningful external constraints. When an agency writes its own rules, conducts its own audits, and answers to no independent authority, the question is not whether distortions will follow, but only when.

Moreover, the circuit court’s rule would invite the warrantless deployment of still more technologies to surveil the public. ALPRs, military-grade drones, financial “audit trails,” and other means let the government monitor millions of people with ease, tracking movements, detecting faces, recording digital conversations, and then storing everything for later review. Left unchecked, such tools result in panopticon.

The Court of Appeals should foreclose a surveillance apparatus that silently records the movements of everyone in South Carolina who dares to venture onto a public street.