Supreme Court Expands Digital Location Data Protections

WASHINGTON – The Supreme Court has affirmed that individuals possess a constitutional right to privacy regarding their digital location data, mandating that law enforcement typically obtain a warrant before accessing such information. The ruling in *Chatrie v. United States* expands protections initially established in *Carpenter v. United States*.

Prior to the *Chatrie* decision, the 2018 *Carpenter* case established warrant requirements for police seeking at least seven days of cell-site location information (CSLI). Cell phone providers generate CSLI as devices connect to cell towers, offering an approximate location within an area ranging from one-eighth to four square miles.

The *Carpenter* court determined that individuals hold a reasonable expectation of privacy in this data. They cited its revealing nature regarding personal movements, its volume exceeding previous tracking capabilities, and its involuntary generation by cell phone users as key factors for Fourth Amendment protection.

*Chatrie* addressed questions regarding digital location data that spans shorter durations or involves more user interaction. The case specifically involved police using a 'geofence' to request data from companies about all cell phones within a defined virtual perimeter. This included data from Google's 'location history' service, which records precise and frequent location information.

Despite differences from CSLI, such as potential user opt-in and shorter data collection periods, the Court concluded that 'location history' data warranted similar protection. The precision of this data and its retrospective accessibility for police to reconstruct movements in both public and private spaces contributed to this determination. The court stated that individuals have a reasonable expectation of privacy in their digital location history.

A central element of the *Chatrie* ruling was the Court's characterization of digital location data as belonging to the user, describing it as a 'personal journal.' This contrasts with CSLI, which users generally do not perceive as their own records. This distinction bolstered the argument for protecting location history data.

The Court also addressed the third-party doctrine, which generally states that individuals lose privacy expectations in information shared with a third party. While *Carpenter* exempted CSLI from this doctrine due to its involuntary nature, the government argued that users voluntarily share location history by opting into services. The Court rejected this argument, stating that using location-tracking apps constitutes 'ordinary things cell-phone users do' and does not negate privacy expectations.

This decision may have implications for other technologies. It could provide a basis for requiring warrants to access AI chat logs. However, questions remain regarding data such as fitness information or data generated on stationary computers. The Court provided limited specific guidance on which records qualify for a continued reasonable expectation of privacy.

Automatic license plate readers (ALPRs) present another area for potential future litigation. ALPR cameras collect and store vehicle location data, allowing for retrospective access. While this information can be revealing, prosecutors may argue that ALPRs only capture movements in public locations, a distinction the *Chatrie* court noted. The extent to which *Chatrie*'s logic applies to ALPRs and other data types remains undecided.

In the *Chatrie* case itself, the Supreme Court returned a key procedural question to the U.S. Court of Appeals for the 4th Circuit. The appellate court will consider the constitutionality of a three-step process used by Google and law enforcement for 'reverse searches.' This process involves Google initially providing anonymized data, then more detailed information for a narrowed list, and finally identifying a smaller subset of individuals. Critics argue this process may lack the particularity required for constitutional searches. Justice Ketanji Brown Jackson elaborated on this concern in a concurring opinion, suggesting that a ruling against this process could effectively prohibit reverse searches. While *Chatrie* established the warrant requirement for this information, the specific type of warrant needed and the legality of such searches remain open questions.