An Explosion in Geofence Warrants Threatens Privacy Across the US

According to Google, new figures show that police have dramatically increased the use of geofence warrants in the United States. This widely-criticized investigative tool collects data from any device found within a specific area and within a given time frame. Google has revealed for the first-time the number of geofence warrants it has received from law enforcement since 2016.
According to the report, requests for assistance have increased tenfold in certain states over the last three years. California law enforcement received 1,909 requests for 2020, up from 209 in 2018. The number of geofence warrants issued in Florida increased from 81 in 2018 to over 800 in 2018. The number of requests for geofence warrants in Ohio rose by 400 to seven during the same period.

Geofence requests to Google rose from 941 in 2018 and to 11,033 by 2020 across all 50 states. They now account for more than 25% of all data requests received from law enforcement.

Because it is so intrusive, it should only be used as a last resort. Jake Laperruque Project on Government Oversight

One request for geofence could contain data from hundreds of people. Nearly 1,500 device identifiers were sent to the Bureau of Alcohol, Tobacco, Firearms and Explosives in 2019 as a result of a single warrant for arson. Many privacy advocates and civil liberties groups have called for the banning of this technique. They claim it violates Fourth Amendment protections against unreasonable search, especially for protesters. Google's transparency report now shows the extent to which individuals across the country may have been subject to the same violation.

Jake Laperruque is senior policy counsel at the Constitution Project, a non-profit organization. Geofence warrants are a broad tool that allows police to access location data of people without criminal connections.

Google stated in a statement to WIRED that it vigorously protects the privacy of its users and supports the important work of law enforcement. This process was created to meet our legal obligations and limit the data that can be disclosed.

Forbes reported this week that Google gave police in Kenosha (Wisconsin) access to user data from anyone who was near a library or museum that was set ablaze last August during protests following the murder of George Floyd. Google provided the GPS coordinates and data as well as device IDs and time stamps to anyone who was present at the library. The museum had the same information for 25 minutes. Minneapolis police also requested Google user data from anyone in the area of a suspected theft at an AutoZone shop last year, just two days after protests started.

Laperruque claims that geofence warrants can have a chilling impact, where people give up their right to protest for fear of being monitored. This week, Kenosha legislators debated a bill making attendance at riots a felony. Critics pointed out that such a bill could make anyone who attends peaceful demonstrations that become violent due to the actions of another person a felony. Geofence data could also be used to prove guilt, not only by being in a crowd with another person but simply by being there.

Geofence warrants are different from standard search warrants. Officers usually identify suspects or persons of interest and then get a warrant from the judge to search the person's home or belongings.

Geofence warrants allow police to request data from Google about the devices around the location where the suspected crime occurred. This is usually done within one-to two hours. Google will provide anonymized data on the devices within the area if it is granted permission. This includes GPS coordinates and the time stamps for when they were there. An anonymized identifier known as a reverse-location obfuscation ID, or RLOI.