What is Geofence Warrant?

Geofence warrants flip the traditional investigation model: instead of identifying a suspect and then obtaining their data, police define a location and time, then demand data on every person who was there.

How They Work

1. A crime occurs at a specific location and time
2. Police draw a geographic boundary (geofence) around the area
3. A warrant compels Google (or other companies) to provide:
   • Step 1: Anonymous device identifiers for all devices in the area during that time
   • Step 2: Police narrow the list and request additional data
   • Step 3: Police request identifying information for specific devices
4. Every person who happened to be near the crime scene becomes a suspect

The Scale

• Google Sensorvault: Database containing location data from hundreds of millions of devices going back nearly a decade
• Google received 11,554 geofence warrants in 2020 alone (a 60% increase from 2019)
• One warrant can return data on hundreds or thousands of devices
• 25% of all law enforcement requests to Google in some jurisdictions are geofence warrants

Why They're Controversial

• Innocent people become suspects: Anyone walking by, living nearby, or commuting through the area is swept up
• Fourth Amendment concerns: The warrant targets a location, not a person — arguably a general warrant (prohibited by the 4th Amendment)
• Chilling effect on assembly: Attending a protest, church, or political meeting makes you a potential suspect in any crime that occurs nearby
• Accuracy issues: Location data can be imprecise, placing innocent people at crime scenes they weren't actually at
• Overuse: Originally for serious crimes, now used for routine investigations

Legal Status

• Google (2023): Announced it would stop storing location data centrally, making geofence warrants infeasible for new data
• Federal courts: Split decisions — some courts have found geofence warrants unconstitutional
• Several states: Considering legislation to ban or restrict geofence warrants
• Virginia (2024): First state to effectively ban geofence warrants

Real Cases

• Innocent cyclist: Zachary McCoy was flagged as a burglary suspect because his cycling route passed near a crime scene
• Kenosha, WI: Geofence warrant encompassed an entire church during a time of political unrest
• Denver: Warrants used to identify people near a protest

How to Protect Yourself

1. Disable Google Location History — Settings → Location → Location History → Off
2. Disable WiFi and Bluetooth scanning — Your phone uses these for location even with GPS off
3. Use airplane mode in sensitive locations
4. Use a de-Googled phone (GrapheneOS) — No Google location services
5. Leave your phone at home when attending events where location data could be compromised
6. Support legislation banning geofence warrants in your state