DATE: August 25, 2026
TO: TOWN MANAGER
__________________________________________________________
Dear Sir or Madam,
We are a civil liberties group headquartered in the Town of Belmont and founded in 2012. We include attorneys, technologists, privacy experts, and ordinary citizens and residents of Massachusetts. We have advised Massachusetts municipalities for many years on surveillance ordinances, policies and technologies. We’re contacting you today about Flock Safety, to provide an update regarding a wave of revocations of municipal contracts for this invasive automated license plate reader technology in Massachusetts.
Police departments in many communities in Massachusetts rolled out Flock Safety cameras during 2024 and 2025. Now, many communities, including Boston, Cambridge, Douglas, East Bridgewater, Framingham, Grafton, Hopkinton, Littleton, Natick, New Bedford, Salem, Stow and Watertown, are revoking their contracts and taking the cameras down. This letter explains why, and discusses the privacy, civil liberties and legal issues with Flock deployments. We strongly urge your Town, if it has a Flock Safety contract, to join other Towns and cities in taking steps to end that deployment, and to not permit the use of ALPR in general in your community.
Flock Safety’s business model
Flock Safety is constructed to facilitate frictionless, nationwide data sharing between law enforcement agencies, creating in effect a nationwide network of 130,000 cameras tracking drivers, and individuals, wherever they go. The value it offers to its law enforcement clients is essentially a network effect: for each marginal jurisdiction added to Flock, the network becomes more valuable to every client that has already joined the network, because suspicious vehicles are often found outside of the jurisdiction where they were initially flagged.
Flock Safety’s product design
Flock’s business model drives its product design. Opening your residents’ location records to Flock means making their location records accessible, for example, to Houston PD, who routinely search all Flock jurisdictions for suspect license plates, hundreds of times a day. Notably, this has enabled out-of-state law enforcement to search the ALPR records of Massachusetts communities adopting Flock for suspected undocumented immigrants, and for many more categories of vulnerable people.
Flock sometimes assures municipalities that they will “own the data”, but their contract terms make clear that the ownership is only of the raw plate reads, which are scarcely valuable in themselves. All interpretation of those raw reads, and all of Flock’s array of AI-driven pattern-sensing premium add-on services, that enable law enforcement to track cars or associated cars or individuals, belong to Flock and Flock only. Nor does municipal “ownership” of the raw data mean that it won’t or can’t be shared onward by Flock. Any law enforcement agency can still search your residents’ location records, at any time and for any reason. Flock holds the data, whether or not the Town technically owns it, and from there can and does modify, interpret, share and sell that data with other private parties and federal agencies, at their discretion.
This business model makes it impossible that Flock will ever protect privacy well, for example by encrypting your residents’ location records so that Flock itself can’t see them, and then requiring law enforcement to provide a probable cause warrant before decrypting them.
Flock Safety’s deceptive practices
Even by one year ago, it had become plain that Flock Safety had a pattern and practice of deceiving municipalities. Municipal officials, often including police departments, want to reassure themselves that the data they share with Flock has reasonable guardrails. Flock Safety representatives have gone to many municipal governments to pitch their product, and have regularly told them that they will not share data with federal government agencies. But one year ago, it emerged that without disclosing it to municipalities, Flock had in fact been sharing data with CBP, in a confidential pilot program. Reporters found later that it wasn’t just CBP; it was ICE, Homeland Security Investigations, the FBI, the Secret Service, and even NCIS. This year, after a wave of contract revocations, Flock Safety representatives have been insisting to cities and towns that their cameras are only about reading license plates. Once again, however, investigative reporting has shown this not to be true: Flock cameras can now be found focused on kids’ playgrounds and gyms, as well as other sensitive off-road locations.
Flock Safety’s lack of competence and care
In Cambridge, MA, the City suspended the Flock contract in October 2025, and ordered Flock to take the cameras down. Then, on the day of a December hearing on whether to permanently revoke the contract, Flock Safety admitted to Cambridge PD that they had reinstalled cameras without the City’s permission. Cambridge has now ended their agreement. Remarkably, this precise sequence of events had previously occurred in Evanston, IL.
Flock’s systems are set up such that law enforcement officers from any jurisdiction can enter in any justification for a license plate search. They can simply say “investigation.” They can also leave it blank. There’s no requirement for the search to be tied to an actual investigation. There’s no constraint to prevent the search being for immigration enforcement reasons, or for personal reasons. No wonder then that in many places, including Stow and Lynn, police officers have been reported to be using the technology to stalk exes. Flock’s newest AI offering, “OS Investigate”, showcases how poor their internal controls are, the dizzying scope of the firm’s ambitions, and that yes, they’re definitely tracking people, not just cars. The ACLU has documented how Massachusetts Flock data has been searched by law enforcement agencies countrywide.
This month, Flock tried to address criticisms by reducing its standard data retention period from 30 days to 7, improving their internal auditing of suspicious searches, and allowing municipalities a nominal power to limit the kinds of searches other law enforcement agencies can perform on their network (i.e., if a law enforcement officer actually discloses that a search is for immigration purposes, a municipality could now bar such searches – but nothing has changed to make them disclose it.). All of this is essentially a token effort. The fundamental software and the business model of Flock cannot exist in the context of proper privacy protections, such as a warrant requirement for searches of automated license plate data that would otherwise be held in an end-to-end-encrypted manner. No ALPR firm adequately protects innocent residents’ privacy; without encryption, records can routinely be accessed by ICE, and other federal or even local law enforcement agencies via an investigative subpoena or even an administrative subpoena. Police have credited Flock Safety with helping to solve individual crimes, but it’s not even clear that automated license plate readers are accurate or reduce crime overall. Your Town’s resources may well be more effectively invested in human services programs than in technologies that reduce people to inaccurate data patterns.
Additional municipal costs relating to public distrust of Flock in particular
There’s considerable public anger on both left and right at the way Flock Safety has been rolled out without the public’s explicit consent. Some communities in Massachusetts – like Lawrence, Brookline, Cambridge, Somerville and Boston – have ordinances providing a mechanism of elected official consent and review for surveillance technologies, but most communities do not, and they should. If it is not meaningfully possible for ordinary residents to block approval of an unpopular police surveillance technology that affects residents’ own rights, then it may be readily deduced that there will be residents willing to take matters into their own hands, by blocking or vandalizing Flock cameras.
Any decision to adopt or continue the use of Flock in your town must take into account the additional costs of possible camera replacement, plus the additional costs of policing to prevent camera vandalism incidents. The case of Winona, MN is instructive here. In this town of 24,000 people, someone as yet unidentified “cut down poles and removed all eight of the city’s Flock cameras.” Faced with a situation of having to repurchase the cameras if they wanted them back up, Winona’s police chief decided not to do so, commenting, “we believe its use has contributed to growing concerns about trust in policing.”
Alternative ALPR vendors also have substantial problems
Some towns abandoning Flock Safety have simply switched to a different vendor. But going with Axon or Motorola or Vigilant won’t fix the problem here. People feel that they aren’t in control of the technologies deployed against them. They won’t feel any more in control of an ALPR camera from a different company, and these other companies’ offerings aren’t better from a privacy standpoint either. Motorola’s commercial plate-scanning infrastructure is marketed to private companies, including auto financers and insurers, and not only for repossession but also for “risk assessment” purposes — even though risk scores have been shown to disproportionately harm low-income and other marginalized drivers. Axon’s PR materials talk cheerily about “integrating hardware devices and cloud software solutions” in “the Axon
ecosystem” and connecting “every officer, responder and agency”, which doesn’t help if outside agencies are targeting your Town’s residents for accessing reproductive or gender-affirming healthcare legal in Massachusetts. ACLU has a good overview of the problems with these systems here.
ALPR systems’ suspicionless searches of location records are now plausibly unconstitutional
The Supreme Court itself, in its June 2026 decision in Chatrie, has now issued a ruling that imperils the future viability of the ALPR sector as a whole.
When your police chief was in the academy, they were probably told that people don’t have a reasonable expectation of privacy in their movements in public, because those movements are public. Till 2012, that information would have been correct. But since then, in a series of decisions (Jones, Riley, Carpenter, and now Chatrie), the Supreme Court has undermined that previous understanding. Now, at least as regards their location records, people do have a reasonable expectation of privacy when in public, which means that collection of such location records are a search; and searches, under the Fourth Amendment, must be reasonable and generally require a warrant. So, ALPR companies find themselves on increasingly shaky legal ground, even if police chiefs aren’t always aware of the fifteen years of fresh jurisprudence that makes it shaky.
The holding in the June 2026 Chatrie decision reads, “Police officers conducted a Fourth Amendment search when they acquired Chatrie’s location data from Google because an individual has a reasonable expectation of privacy in his cell-phone location information.” The reasoning, however, is not limited to cell-phone location information, and lower courts are very likely to apply Chatrie to ALPR technology. Prior Supreme Court decisions in Jones (2012) and Carpenter (2018) suggested that location records might only be a search if they covered a sufficient period of time that police could detect the pattern of one’s movements in public – which Flock Safety definitely allows police officers to do with respect to a particular vehicle. But Chatrie goes further than this, saying, “the Government is wrong about the incapacity of short-term location information to reveal private matters.” Even short-term location information – like a single ALPR snapshot – can potentially reveal a person’s preferences, habits, and beliefs, and thereby be considered a search. The Court refers to “sweeping” location-identifying methods—as distinguished from merely “rudimentary” location-identifying methods—and rules that the former constitute a “search.” It is hard to argue at this point that a nationwide network of over 130,000 AI-searchable cameras like the one Flock Safety offers, is not “sweeping.”
There was advance warning of these legal problems, and we have been trying to alert Towns and cities to them. 2021’s Commonwealth v. McCarthy decision by the Supreme Judicial Court noted that, while the specific ALPR deployment at issue in the case (on the Sagamore Bridge down to Cape Cod) was lawful under the Massachusetts Constitution, it was possible for ALPR deployments to form a dense enough pattern in residential neighborhoods that they would be “too permeating police surveillance,” and therefore trigger a warrant requirement. The Flock Safety deployments round your way may not, or may not yet, reach this level of density; but this adds a further layer of legal risk to the Town, not just from the fact of the deployment of ALPR, but from the manner of it.
Conclusion
We therefore advise strongly, in the light of these facts and rulings, that you have a conversation with your Town solicitor to confirm the points raised above, and take action to protect the privacy of your residents. We are ready to assist with this process, as we have done in other municipalities; I’m available at 617-208-9002 for further discussion.
Sincerely,
Alex Marthews and Julie Bernstein
Co-Chairs, Digital Fourth.
