The U.S. Supreme Court’s ruling on Friday that the government generally needs a warrant to access cellphone location data is not just a win for digital privacy advocates — it’s also a victory for the tech giants that make money off your data.

In a 5-4 opinion written by Chief Justice John Roberts, the high court ruled that the government does not have a right to access that data without a warrant simply because you “shared” that information with your wireless carrier.

“This is a ruling that means that the government will have a very hard time figuring out where our cellphone has been for any length of time. But I think the importance of the opinion goes well beyond that,” Lior Jacob Strahilevitz, a professor at the University of Chicago Law School, told Yahoo Finance.

“We’ve entered an age in which people are constantly sharing lots of information about themselves with Google or with AT&T or with their internet service provider. All of the sudden the fact that that information is being shared does not mean that the government can get that information without a search warrant,” added Strahilevitz, who co-authored an amicus, or “friend of the court,” brief in this case.

‘Companies are going to be happy with this ruling’

That could be a good outcome for tech companies for a couple of reasons. For one thing, tech giants spend a lot of time and money complying with government requests for third-party information like cellphone location data. If governments have to go through the hassle of getting a warrant for that information, they’ll likely be making fewer of those kinds of requests.

Moreover, tech companies have a vested interest in their users operating under the assumption that the authorities can’t easily access their personal data.

“People might now feel as though they can turn on location services or they can keep their cellphone activated … without running the risk that this might ultimately end up falling into the government’s hands. And I think the technology companies might want us using those devices as much as possible. They want to gather a lot of this data and monetize it for marketing purposes,” Strahilevitz said.

America’s biggest tech companies — including Apple (AAPL), Facebook (FB), Google (GOOG, GOOGL), and Yahoo Finance parent Verizon (VZ) — expressed their interest in this case in their own amicus brief. While that brief technically supported neither side, the tech giants hinted that the court should reconsider whether the government should easily be able to get its hands on that data. At the same time, they seemed to want to ensure that companies can access that data for their own purposes.

“Because the data that is transmitted can reveal a wealth of detail about people’s personal lives … users of digital technologies reasonably expect to retain significant privacy in that data, notwithstanding that technology companies may use or share the data in various ways to provide and improve their services for their customers,” the brief said. “Fourth Amendment doctrine must adapt to this new reality.”

As Strahilevitz said, “Companies are going to be happy with this ruling.”

A ‘narrow’ ruling with big implications

The decision on Friday sides with Timothy Carpenter, who was convicted of, ironically, stealing smartphones at several Radio Shack and T-Mobile (TMUS) locations.

Carpenter was convicted after police obtained records showing that he’d used his cellphone in the vicinity of several of the robberies. In fighting his conviction, he contended that the government violated his Fourth Amendment right against unreasonable searches by obtaining those records without a warrant.

In a decision joined by the court’s four more liberal justices, Roberts stressed that he was making a “narrow” ruling that did not call into question conventional police surveillance techniques like security cameras. However, the ruling could have implications beyond just cellphone records, according to three legal experts.

For decades, the high court has said that when you share your information with a third party, like a bank or telephone company, you lose the expectation that it will remain private. This decision has changed that precedent, according to Jennifer Daskal, an associate professor of law at American University.

“Going forward, it means the government can no longer rely on the fact that data has been turned over to third parties to demand disclosure without a warrant,” she said, noting that the decision reflects the justices’ “recognition of the need to update Fourth Amendment doctrine to match the reality of modern technology.”

‘Indispensable to participation in modern society’

Roberts’s opinion recognizes just how far technology has come since the court initially ruled that any information that you “share” with a third party is fair game for the police to obtain without getting a warrant first.

“Cell phone location information is not truly ‘shared’ as one normally understands the term. In the first place, cell phones and the services they provide are ‘such a pervasive and insistent part of daily life’ that carrying one is indispensable to participation in modern society,” Roberts noted.

In previous opinions, the Supreme Court has suggested that people assume the risk that their information won’t be private anymore once they use technology like cellphones, Strahilevitz said. With this decision, Strahilevitz noted, Roberts wants to stress that “cellphones aren’t optional anymore.”

And while Roberts’s opinion is limited to cellphone location data, it’s easy to imagine the reasoning applying to information you share with technology providers like Facebook or Google, according to Jonathan Manes, an assistant clinical professor at the School of Law at the University at Buffalo.

“These days, companies hold so much information about all of us because the business model is that the company holds information in the cloud in order to make services useful and easy,” Manes noted. With the latest Supreme Court decision, he noted, “Just because the company holds it doesn’t mean that the government can get it without a warrant.”

Ultimately, this is a new precedent that both big tech companies and privacy advocates will be able to get behind.

Erin Fuchs is deputy managing editor at Yahoo Finance.

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