The Supreme Court’s ruling has challenged the government’s use of geofence permits

Just as carrying a cell phone is a part of modern life, so allowing another party to monitor your movements, and this does not diminish a person’s right to privacy, the majority ruled. Justice Sonia Sotomayor said that “even a short surveillance” of a person can reveal “a lot (of) information about (about) his family, political, professional, religious, and sexual relations”—especially if he has been seen visiting sensitive places, such as a hospital, a lawyer’s office, or a strip club.

Kagan wrote: “People expect privacy about the location of their phone, and law enforcement violates that legitimate interest when they want to know — even for a short period of time, and from another technology company,” Kagan wrote.

Privacy advocates were pleased with the decision, although it “stopped challenging the documents as unconstitutional,” Andrew Crocker, director of litigation at the Electronic Frontier Foundation, said in a statement provided to Ars.

“We applaud the Court’s decision,” Crocker said. “The court reaffirmed that you have an expectation of privacy in the content that reveals your natural movements, and that even the briefest observation of these movements is subject to Fourth Amendment scrutiny.”

Technology companies also moved to support the resolution. Matt Schruers is CEO of the trade association that counts Google and Apple among its members, the Computer & Communications Industry Association. In his speech, he celebrated the decision making it clear that “the Fourth Amendment fully protects the right of individuals to privacy from government interference.”

“We are encouraged to see the Court recognize that privacy continues regardless of the technology involved, and that law enforcement must obtain a court order to access American information,” Schruers said.

Inconsistencies are caused by software-by-software

The majority of judges agreed that the same standard that the Fourth Amendment applies to all location data was necessary to avoid future court disputes that could draw different lines between different software and phone features.