Remember United States v. Jones? It was the January 2012 case in which the US Supreme Court decided unanimously that law enforcement does not have the right to warrantlessly put a GPS tracking device on a suspect’s car. (In the wake of that decision, the FBI turned off 3,000 such tracking devices.)

While the Supreme Court ruled on that important element of the case—reversing the plaintiff's life sentence on federal drug charges—the case (minus the invalidated GPS evidence and everything stemming from it) was sent back down to a lower court to be re-tried.

In addition to GPS tracking, federal prosecutors asked for (and obtained) court-ordered access to Antoine Jones' cell-site data in 2005. Late this year, Jones’ attorneys filed a motion to have that location and behavioral data suppressed during a recent pretrial proceeding, citing the precedent Jones set with his Supreme Court hearing.

Last Friday, the judge on the case denied that motion (PDF), siding with federal prosecutors and saying the agents involved were operating in “good faith.”

"Because at the time of the applications in this case it was reasonable for the officers to seek an order authorizing the disclosure of cell-site data, it was also reasonable for them to rely on the magistrate judges’ orders granting those applications," Judge Ellen Segal Huvelle wrote, citing legal precedent for this line of reasoning.

That decision falls generally in line with many other court orders validating law enforcement’s investigative power to surveil and monitor criminal suspects, even if the police can't put a physical device on a car. Such court orders—which can include what’s called a “(d) order,” or a pen register—require a judge’s approval, but not a warrant. These court orders of a lower legal standard likely gave investigators information about who Jones called, when, and where he was when he did so.

As we’ve reported before, other types of high-tech surveillance and monitoring continue being used by law enforcement on a daily basis around the country. Cops are using everything from tap and trace, ping data, license plate surveillance, and other techniques as a way to keep tabs on suspects and innocent citizens without going through the threshold of a judicially reviewed probable-cause-driven warrant. Historically, judges and courts have been reluctant to halt or slow such requests, but there have been some exceptions in recent years.

Still, the judge presiding over the Jones case, Judge Huvelle, declined to rule on the over-arching question that we all want to know: does the Fourth Amendment, which prohibits unreasonable searches and seizures, require that cops get a warrant if they want to track us by any means? Or can our cellphones be used against us as tracking devices?

“The Court, however, need not resolve this vexing question of Fourth Amendment jurisprudence, since it concludes that the good-faith exception to the exclusionary rule applies,” she wrote.

Privacy experts hoped this would continue to raise broader questions about the boundaries between law enforcement and digital privacy, though.

“In the grand scheme of things, this case is not that big of a deal,” Hanni Fakhoury, staff attorney at the Electronic Frontier Foundation, told Ars. “It's saying that in 2005, the law was unsettled and [the judge said] ‘I'm not going to find their conduct unreasonable and because of that I'm not going to touch the legal issue as to whether people have a legal expectation of privacy even though they turned them over to the provider.’”

Reasonable expectations of privacy in the digital age

The judge here cited the “third-party doctrine," which is the idea that individuals have no “reasonable expectation of privacy” when they give up information with a company or government agency.

In this case, any cellphone user has to give up his or her location to the mobile phone company so they can be provided with service. The logic goes that because an individual has given up that location information to the company, it therefore cannot be considered private in the first place.

“There's a ton of questions left unanswered,” Fakhoury added. “It's coming up on the one-year anniversary [of Jones] and it's a good time to reflect and think about what's happened [privacy-wise], and the reality is, not much.”

While this new opinion in the Jones case may be disappointing for privacy advocates including the EFF, which wrote an amicus brief for Jones in the case, there may be a chance for courts to more fully evaluate digital privacy in the future.

After all, in the Supreme Court decision (PDF) Justice Sonia Sotomayor wrote her concurring opinion that the entire third-party doctrine may need to be reconsidered.

“I would take these attributes of GPS monitoring into account when considering the existence of a reasonable societal expectation of privacy in the sum of one’s public movements,” she wrote. “I would ask whether people reasonably expect that their movements will be recorded and aggregated in a manner that enables the Government to ascertain, more or less at will, their political and religious beliefs, sexual habits, and so on.”

“This approach is ill-suited to the digital age, in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks,” she concluded.