Photos by Scott Webb/ Unsplash, Thomas Scott/Unsplash, and Shawn Tung/Unsplash.

Neighbors have always been able to spy on you. Watchful eyes behind curtains eventually turned into security cameras on porches. But these forms of self-protection have always been limited to what people can see and identify. But what happens when you fuse startup culture, artificial intelligence, and fearful neighbors? Call it the rise of networked vigilante surveillance. And we’re not prepared for it.


A new venture called Flock Safety is a good example of the problem. The Atlanta-based company sells a particular vision of security: Residents can track every single car that passes through their neighborhood with the help of the company’s automatic license plate readers. As the Los Angeles Times recently reported, a two-year contract entitles you to the cameras, cloud storage for the data, and, most importantly, software that allows quick identification of license plates—completing a task in seconds that would take a person hours or days. (It’s not necessary for a whole neighborhood to agree to adopt the system, as long as some neighbors agree to pay for it.) If a crime happens within the neighborhood, residents can check and see which cars were captured by the cameras in the area at the time. Imagine being able to produce a detailed map of one car’s whereabouts. Residents can send videos to the police, and the police can presumably request data from residents. Although the data is stored on the company’s servers, residents own the data, according to the company’s website.

In this way, suspicious neighbors are just catching up to the police, repo agents, and property managers, who already have access to license plate readers that can capture data at rates of thousands of plates per minute. Flock essentially tells potential customers: If these are useful tools for safety, shouldn’t individuals and communities have them, too? And like many other surveillance products sold to the police and the public, it promotes surveillance as a service with a for-profit motive. The company begin as a 2017 Y Combinator startup and has since raised millions in venture capital funding from Peter Thiel’s Founders Fund, among others. Its website promises to “increase solvability around crime with infrastructure-free [automatic license plate readers] in your community.”

The drive to move fast and sell quickly is especially ill-suited to a product of mass surveillance controlled by your neighbors. Maybe your neighborhood would have a trusted group soliciting input from everyone about how to run its ALPR network before signing up. Or maybe it wouldn’t. Maybe your systems administrator is the most ethical person on the block. Or maybe you grant everyone in the neighborhood access to the footage, as Flock permits. Flock provides a product; it doesn’t provide training in the law or in ethics. Nor would we expect it to—civilians aren’t law enforcement professionals.

But unleashing an automatic license plate reader system to groups of private citizens with a handshake and a contract means these systems are ripe for abuse. Once some residents in your neighborhood can track every license plate, they will face some unsavory temptations. Imagine a neighbor who wants a shot-by-shot map of the whereabouts of a spouse, a neighborhood child, or an unconventional resident. Or someone who wants to count the times your “suspicious” friends have come to visit the neighborhood. While automatic license plate reader cameras are sold as a crime prevention measure, there’s nothing to stop their use as tools of harassment or stalking.


And sometimes the software will be plain wrong. There is little for the wrongly accused people to clear their names. As for Flock? It’s not the company’s problem. As its head of marketing states, using the software inappropriately would be a “breach of contract.” But that is hardly a mechanism for accountability.

There seems little to stop those impulses from becoming even worse when social media can amplify some of our worst social traits. Why not collect lists of “suspicious” cars and plates and post them on Facebook or NextDoor? Why not combine these lists with videos from Ring video doorbells? If you’re the lone neighbor who doesn’t want any part of this, you have little choice other than to leave your community altogether. That is, if you even know your neighbors have installed an ALPR system.

The direct marketing of such products to individuals raises perhaps the most worrisome concern: encouraging vigilantism. These extralegal movements, organized to take the law into one’s own hands, have long been with us. Think back to Bernie Goetz in 1980s New York, the North Ward Citizens’ Committee in 1960s Newark, and even further back to the San Francisco Vigilance Committee of 1856. Or just remember the tragic circumstances of Trayvon Martin’s death at the hands of George Zimmerman, who was a neighborhood watch volunteer. Now imagine a community automatic license plate reader network that issues a BOLO (“be on the lookout”) for a particular car. Then what?


Vigilante justice arises when people feel the usual methods of addressing crime are broken or flawed. In his classic 1975 study “Strain of Violence,” historian Richard Maxwell Brown observed that American vigilantism is an indigenous and deeply rooted part of our shared history. We have a lot of experience with private citizens meting out their own versions of justice, and it is largely an ugly one.

These new technologies prey upon familiar fears—that local police ignore or dismiss crimes important to neighbors—and hyper-charge them with the power of surveillance. The potential concerns they raise are similar to the ones we see as law enforcement agencies and private corporations adopt these tools, but with even fewer guardrails. Neighborhoods armed with Ring videos, Flock readers, and NextDoor posts have the power to create networked engines of suspicion, sometimes ill-founded or erroneous, that may embolden residents to take actions they should not.

And even if neighborhoods armed with ALPR do nothing more than watch and post, the harms are significant nonetheless. The erosions of our privacy are coming from the government, corporations, and now our neighbors.