Judges in Pierce County, Washington, have now begun requiring law enforcement agencies to ask for specific permission when using a cell site simulator, commonly known as a "stingray," according to a Saturday report by the Tacoma News Tribune.

Previously, as is the case nearly everywhere else in the country, law enforcement would go to a judge asking for a "pen register, trap and trace" order, which in the pre-cellphone era allowed law enforcement to obtain someone's calling metadata in near real-time. Now, that same data can be gathered directly by the cops themselves through the use of a stingray used against mobile phones. Stingrays, however, also can be used to intercept calls and text messages, and the stingray doesn't only work against one target phone but also against other phones that may happen to be nearby.

The new, more stringent standard is unusual among American courts.

After the Tacoma newspaper published a story in August 2014 detailing how the devices were used locally, the county's 22 Superior Court judges, "who first learned of the police department’s cell site simulator from the News Tribune's reporting, now require language in pen register applications that spells out police intend to use the device.”

In addition, the paper noted that "law enforcement agencies that want to deploy the device also must swear in their affidavits that they will not store data collected from people who are not the target of the investigation.”

The court did not immediately respond to Ars' request for comment over the weekend.

At least one privacy-minded former judge lauded the Pierce County decision.

"I think the argument that judges need not know about the aspects of cell site simulators before they sign off on them is wrong," Brian Owsley, a former federal magistrate judge in Texas and now a law professor at Indiana Tech, told Ars by e-mail. "It runs counter to the Fourth Amendment. In order for a judge to properly assess whether there are any Fourth Amendment concerns, a judge must know exactly what she or he is considering authorizing. Otherwise, a judge cannot properly determine whether there is probable cause consistent with the Constitution."

"I think the standards outlined are consistent with my decision denying a cell site simulator in part because of concerns about third party information. It is similar to the protocol I outlined in a decision on cell tower dumps. I think judges should be expecting law enforcement to be candid with the court about how they are using the devices and what they are doing with innocent people's data.”