GoKawiilEvery time you unlock your smartphone or start your connected car, you are generating a trail of digital evidence that can be used to track your every move.
In Your Data Will Be Used Against You: Policing in the Age of Self-Surveillance, just published by NYU Press, law professor Andrew Guthrie Ferguson exposes how the Internet of Things has quietly transformed into a vast surveillance network, turning our most personal devices into digital informants. The following excerpt explores the concept of “sensorveillance,” detailing the specific mechanisms—such as Google’s Sensorvault, geofence warrants, and vehicle telemetry—that allow law enforcement to repurpose consumer technology into powerful tools for investigation and control.
This article is adapted from the author’s new book, Your Data Will Be Used Against You: Policing in the Age of Self-Surveillance (NYU Press, 2026).
A man walked into a bank in Midlothian, Va., his black bucket hat pulled low over dark sunglasses. He handed a note to the teller, brandished a gun, and walked away with US $195,000. Police had no leads—but they knew that the robber had been holding a smartphone when he entered the bank. Guessing that the smartphone, like most smartphones, had some Google-enabled service running, police ordered Google to turn over information about all the phones near the bank during the holdup. In response to a series of warrants, Google produced information about 19 phones that had been active near the bank at the time of the robbery. Further investigation directed the police to Okelle Chatrie, who was ultimately charged with the crime. Cathy Bernstein had a tough time explaining why her own car reported an accident to police. Bernstein had been driving a Ford equipped with 911 Assist, which was automatically enabled when she struck another vehicle. Rather than stick around to trade insurance information, she sped away. But her smart car had registered the bump—and called the police dispatcher, leading to a fairly awkward conversation:
Computer-Generated Voice: Attention, a crash has occurred. Line open. 911 Operator: Hello. Can anyone hear me? Unidentified Woman: Yes, yes. 911 Operator: Okay. This is 911. You’ve been involved in an accident. Unidentified Woman: No. 911 Operator: Well, your car called in to us because it said you’d been involved in an accident. Are you sure everything’s okay? Unidentified Woman: Everything’s okay. 911 Operator: Okay. Are you broke down? Unidentified Woman: No, I’m fine. The guy that hit me—he did not turn. 911 Operator: Okay, so you have been involved in an accident. Unidentified Woman: No, I haven’t. 911 Operator: Did you hit a car? Unidentified Woman: No, I didn’t. 911 Operator: Did you leave the scene of an accident? Unidentified Woman: No. I would never do anything like that.
Apparently, Bernstein did do something “like that.” She was soon caught and cited for leaving the scene of the accident. Her own car provided evidence of her guilt.
The Rise of “Sensorveillance”
Once upon a time, our things were just things. A bike was a tool for biking. It got you from one location to another, but it didn’t “know” more about your travels than any other inanimate object did. It was dumb in a comforting way, and we used it as intended. Today, a top-of-the-line bike can track your route and calculate your average speed along the way. Hop on an e-bike from a commercial bike share, and it will collect data for your trip, plus the trips of everyone else who used it that month.
These “smart” objects belong to what technologist Kevin Ashton named the Internet of Things. Ashton proposed adding radio-frequency identification (RFID) tags and sensors to everyday objects, allowing them to collect data that could be fed into networked systems without human intervention. A sensor in a river could monitor the cleanliness of the water. A tag on a bottle of shampoo could trace its journey throughout the supply chain. Add enough sensors to enough objects and you can model the health of an entire ecosystem—or learn whether you’re sending too much of your inventory to Massachusetts and too little to Texas.
Ashton first theorized the Internet of Things (IoT) in the late 1990s. Today, the IoT goes well beyond his initial vision, including not only RFID tags but also sensors with Wi-Fi, Bluetooth, cellular, and GPS connections. These small, low-cost sensors record data about movement, heat, pressure, or location and can engage in two-way communication.
... continue reading