The Fourth Amendment protects Americans from unreasonable searches. If the FBI wants to track where you have been, who you have met with, and what locations you visit, they are supposed to obtain a warrant signed by a judge based on probable cause. The Supreme Court confirmed this in Carpenter v. United States (2018), ruling that accessing historical cell phone location data constitutes a search requiring a warrant.
But law enforcement found a loophole. Instead of compelling phone companies to hand over location data — which requires a warrant — government agencies simply purchase the same data from commercial data brokers. The legal theory is that if you consented to sharing your location with an app, and that app sold your data to a broker, the government can buy it without triggering Fourth Amendment protections.
The result is a shadow surveillance system where your phone's location history is available to any government agency with a budget, no judicial oversight required.
The pipeline starts with the apps on your phone. When you install a weather app, a coupon app, a coffee shop loyalty app, or any free app that requests location access, you are typically consenting — buried in the terms of service — to share your location data with advertising networks. These advertising networks sell the data to aggregators. The aggregators sell it to brokers like Venntel and Fog Data Science. The brokers sell it to the government.
Your phone broadcasts a unique identifier called a Mobile Advertising ID. On iPhones, this is the IDFA (Identifier for Advertisers). On Android, it is the GAID (Google Advertising ID). This identifier is attached to every location ping your apps send, allowing brokers to track a single device — and by extension, a single person — across all their movements.
A 2018 report found that over 10,000 apps were harvesting location data for profit, including seemingly benign apps like flashlight utilities, weather checkers, and coupon clippers. Some apps from smaller developers are essentially fronts for data collection — they provide minimal functionality while continuously reporting your GPS coordinates to data brokers.
With access to commercial location data, law enforcement can perform two types of searches that would traditionally require warrants.
An area search — also known as geofencing — allows officers to draw a virtual boundary on a map and identify every device that was within that area during a specified time window. This is a reverse search: instead of starting with a suspect and tracking their movements, investigators start with a location and time and identify everyone who was present. Innocent people's data is routinely caught in these sweeps.
A device search allows officers to input a specific device identifier and retrieve its location history — where it sleeps at night (likely the owner's home), where it goes during the day (likely their workplace), and every other location it visits. Fog Data Science advertises this as providing a person's "pattern of life."
The geographic range of these searches can be enormous. Fog Data Science allows searches spanning up to 12 miles wide, and location history can be retrieved dating back 180 days.
In Gainesville, Florida, an avid cyclist named Zachary McCoy was identified as a burglary suspect because his phone's location data showed him biking past the scene — something he did almost every day. He spent thousands of dollars on a lawyer to clear himself.
In Arizona, Jorge Molina was arrested for murder based on geofence data that placed his device at the scene. He had an alibi and could show that the data placed his account in multiple locations simultaneously, proving it was unreliable. He was still jailed for six days, his photo was broadcast to media, and he lost his job, his car, and his financial stability.
In Sedgwick, Kansas, police chief Lee Nygaard used Flock Safety's license plate reader system to track his ex-girlfriend and her new boyfriend 228 times over four-plus months, at one point using his own police vehicle to follow them out of town. He was fired and lost his police certification over the misuse.
On iPhone: Settings, Privacy and Security, Tracking, Apple Advertising. On Android: Settings, Privacy (or Google), Ads. Your Advertising ID is displayed there. Copy it before proceeding to Step 3.
Email privacy@venntel.com with your Advertising ID and request deletion of all data associated with that identifier. Visit fogdatascience.com/opt-out and submit your Advertising ID. Visit Babel Street's OneTrust portal and click Delete My Data. Email privacy-requests@clearview.ai and request deletion of any facial recognition data associated with you.
After submitting opt-out requests with your current ID, delete it from your phone. On iPhone: Settings, Privacy, Tracking, toggle off Allow Apps to Request to Track. On Android: Settings, Privacy, Ads, Delete Advertising ID. This breaks the tracking chain going forward — new app activity cannot be linked to your historical data.
Review every app on your phone that has location access. For each one, ask: does this app genuinely need my location to function? Weather apps, coupon apps, and most social media apps do not need constant location access. Set location permissions to "Only While Using" or "Never" for any app that does not require it. The fewer apps with location access, the fewer data points entering the surveillance pipeline.
These brokers continuously collect new data. A one-time opt-out is not permanent. You must resubmit deletion requests regularly. The FTC requires Venntel to check for deletion requests at least every 45 days. Match that cadence with your resubmissions.
The uncomfortable truth: Most data removal services completely ignore government surveillance brokers. They focus on people-search sites like Spokeo and WhitePages while Venntel and Fog Data Science continue selling your location to law enforcement. If your privacy service does not target these four companies, it is leaving your most sensitive data exposure completely unaddressed.
The Fifth Circuit Court of Appeals ruled in 2024 in United States v. Smith that geofence warrants are unconstitutional "general warrants" under the Fourth Amendment. The Fourth Circuit reached a different conclusion in United States v. Chatrie, finding no search occurred because the defendant had voluntarily exposed his location data to Google. That circuit split went to the Supreme Court, which ruled in June 2026 in Chatrie v. United States that a geofence warrant seeking location history does constitute a Fourth Amendment search — a significant win for privacy advocates, though the Court left the question of exactly when such warrants are valid to the lower courts.
The ruling addresses geofence warrants specifically — a court compelling a company like Google to hand over location data for a given area and time window. It does not directly resolve the separate practice this article is about: the government simply buying the same kind of location data from commercial brokers like Venntel, sidestepping the warrant question entirely. The House-passed Fourth Amendment Is Not For Sale Act, which would close that purchasing loophole, has not been enacted.
Until the law catches up with the technology, the only defense available to individual Americans is to opt out of the data collection pipeline directly — by deleting your advertising ID, restricting app permissions, and sending deletion demands to the brokers that feed the surveillance system.
Vigilant Privacy sends CCPA deletion demands to Venntel, Fog Data Science, Babel Street, and Clearview AI as the first batch for every new subscriber. No other privacy service does this. We also target 2,411 additional data brokers, car manufacturers, and consumer reporting agencies. Zero tracking. Veteran-founded. $9.95/month.
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