Legal Issues
Flock Safety, Privacy & the Constitution
When Does Public Observation Become Government Surveillance?
Flock Safety raises serious constitutional concerns under both the Fourth Amendment to the United States Constitution and Article 14 of the Massachusetts Declaration of Rights.
A single observation of a license plate on a public road is generally not considered a search. The constitutional issue changes, however, when automated cameras continuously collect vehicle locations and those observations are stored, searched, and combined across a network to reconstruct an individual’s movements.
In Commonwealth v. McCarthy (2020), the Massachusetts Supreme Judicial Court specifically considered the constitutional implications of Automated License Plate Readers (ALPRs). Although the Court found that the limited network at issue in that particular case did not violate the defendant’s constitutional rights, it recognized that an individual has a constitutionally protected expectation of privacy in the whole of his or her public movements—and that widespread use of ALPRs could implicate that privacy interest.
The question therefore is not simply whether police may see a license plate on a public street.
The question is whether government should be permitted to build a searchable system capable of determining where ordinary citizens have traveled, when they were there, and what patterns of association their movements reveal—without suspicion, probable cause, or a warrant.
Massachusetts Supreme Judicial Court
“The whole of his public movements”
“[T]he defendant has a constitutionally protected expectation of privacy in the whole of his public movements…”
— Commonwealth v. McCarthy, 484 Mass. 493 (2020)
The Court went on to explain that this interest “potentially could be implicated by the widespread use of ALPRs.”
That distinction is critical.
Seeing a vehicle pass one police officer on one public street is one thing. Creating a system that can search thousands or millions of time-stamped observations to determine where a vehicle has traveled over days, weeks, or months is something very different.
United States Supreme Court
Going into public does not eliminate Fourth Amendment protection
“A person does not surrender all Fourth Amendment protection by venturing into the public sphere.”
— Carpenter v. United States, 585 U.S. 296 (2018)
In Carpenter, the Supreme Court recognized that individuals can have a reasonable expectation of privacy in the whole of their physical movements, even though individual movements take place in public.
Modern technology changes the surveillance equation. What once would have required teams of police officers following someone continuously can now potentially be accomplished by searching an electronic database.
Surveillance Can Affect Freedom of Association
Justice Sonia Sotomayor warned about this problem in her concurrence in United States v. Jones (2012):
“Awareness that the Government may be watching chills associational and expressive freedoms.”
— Justice Sonia Sotomayor, United States v. Jones, 565 U.S. 400 (2012), concurring
She also warned about the government’s ability to assemble information that reveals private aspects of a person’s identity.
Why does this matter?
A single license-plate observation may reveal very little.
But a history of locations can reveal patterns:
Home → place of worship → medical office → political meeting → friend’s home → workplace
The individual observations occurred in public. The assembled pattern can reveal considerably more about a person’s private life, relationships, beliefs, health, political activity and associations.
Massachusetts Provides Its Own Constitutional Protection
The Massachusetts Constitution contains its own protection against unreasonable government searches.
Article 14 of the Massachusetts Declaration of Rights, adopted in 1780, states:
“Every subject has a right to be secure from all unreasonable searches, and seizures, of his person, his houses, his papers, and all his possessions.”
Article 14 predates the federal Fourth Amendment and provides an independent source of constitutional protection for Massachusetts residents.
The Fourth Amendment
The Fourth Amendment to the United States Constitution states:
“The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”
The fundamental principle is simple:
Government surveillance should have limits.
What Does This Mean for Medway?
The issue before Medway is larger than the eight cameras physically located within our town.
Modern ALPR technology makes it possible for individual camera observations to become part of a larger searchable system. As networks become larger, the ability to reconstruct people’s movements becomes increasingly powerful.
That is precisely why the Massachusetts Supreme Judicial Court’s warning in McCarthy is important:
A constitutionally protected privacy interest “potentially could be implicated by the widespread use of ALPRs.”
The Court did not rule that every ALPR system is unconstitutional. Nor did it rule that photographing a visible license plate is unconstitutional.
Instead, it recognized the important constitutional line that communities such as Medway must consider:
At what point does observing cars on public roads become a system for tracking people?
We do not need to wait for a court to declare a particular surveillance network unconstitutional before deciding that it is inappropriate for our community.