US Supreme Court Limits Geofencing, Police Can't Arbitrarily Track Cell Phone Locations

Illustration of a digital map application on a mobile phone that displays location data. The United States Supreme Court ruled that law enforcement officers must have a valid warrant before accessing geofencing data. (Illustration: AI)

JAKARTA - The United States Supreme Court strengthened the protection of the privacy of mobile phone location data. In a 6-3 ruling on Monday, law enforcement officers are required to have a valid warrant before conducting a geofence search.

Citing CNET, Tuesday, June 30, the ruling in the Chatrie v. United States case confirmed that digital location data on mobile phones is private. The government cannot simply ask tracking data from technology companies without a strong legal basis.

In a ruling written by Justice Elena Kagan, the Supreme Court said a person has a reasonable expectation of privacy over his or her cell phone location records. The geofencing warrant was deemed to interfere with constitutionally protected interests.

Geofencing is commonly used by the police when a case does not have a clear suspect. The police create an area limit on the map around the crime scene, determine a certain time range, then ask technology companies to submit device data that is in that area.

This method has been criticized because it not only catches potential suspects. Data on other people who happen to pass by, work, shop, or live in the area can also be collected.

The Supreme Court considers that users do not always voluntarily share their personal data with companies such as Google. Therefore, the third party doctrine does not apply in this case. The third party doctrine is a legal principle that states that a person has no expectation of privacy over data that is voluntarily provided to another party.

With this ruling, the Fourth Amendment of the US Constitution, which prohibits unreasonable searches and seizures, also protects users from overly broad geofencing warrants.

However, the Supreme Court did not ban geofencing entirely. The police can still use such data, but must have a sufficient basis of suspicion against the suspect and obtain a more limited search warrant.

Critics have long viewed geofencing as reverse profiling. The police use location data to find out who might be the perpetrator, rather than starting with evidence that first leads to someone.

Google is one of the technology companies most frequently asked for data like this. In recent years, Google has moved user location data from Sensorvault servers to user devices. Even so, the police can still request location data directly from the phone through a warrant.

The term geofencing itself is not only used in law enforcement. This location-based technology is also used for smart homes and digital advertising. However, this Supreme Court ruling only applies to legal warrants.

This matter began with the arrest of Okello T. Chatrie in 2019. He was linked to a bank robbery worth 195,000 US dollars after the authorities asked for Google data to track devices around the bank during the incident. The list of potential suspects was then narrowed from 19 people to three people, eventually leading to Chatrie.

Chatrie's lawyer, Adam Unikowsky, argued that the police did not have sufficient grounds for suspicion to trace his client's information. According to him, the government uses a tool that allows the police to search first, then build suspicion later.

Unikowsky also argued that a follow-up warrant would still be unconstitutional if it was only based on a person's proximity to the crime scene.

It is not yet clear how this ruling will affect previous cases, including Chatrie's case. The court previously stated that Chatrie's sentence had not changed because the geofencing evidence was obtained in good faith. However, the Supreme Court's ruling has made the validity of the warrant questionable again.

Chatrie's case is now back in a lower appeals court. The court will assess whether there is sufficient evidence to issue a geofencing warrant.