"But the most prominent change regarding stingrays came in September 2015, when the DOJ said it would require a warrant in most situations in which a stingray is used. The policy, which took effect the day it was announced (September 3, 2015), applied to numerous agencies, including the FBI; the Bureau of Alcohol, Tobacco and Firearms; the Drug Enforcement Administration; and the U.S. Marshals Service, among others.
The new state laws and federal policies came as a result of dogged activism by the ACLU and other privacy groups, which all stemmed from Rigmaiden’s case. After all, it was Rigmaiden who had initially reached out to Soghoian and presented him with a 200-page memo on a technology that few outside the government had known about. “It was the most well-researched memo I’d ever seen on this technology,” Soghoian later told WNYC. “Written by a guy rotting in jail.”
Now that lawyers know what to look for and how to challenge them, some of those efforts have been successful. Notably, in March 2016 a state appellate court in Maryland took local law enforcement to task, and ruled unequivocally: “We determine that cell phone users have an objectively reasonable expectation that their cell phones will not be used as real-time tracking devices through the direct and active interference of law enforcement.” The three-judge panel in the State of Maryland v. Andrews case also noted that such a non-disclosure agreement is “inimical to the constitutional principles we revere.”
In other words, judges now seem to be resoundingly echoing the 1967-era Supreme Court language—“reasonable expectation of privacy”—of a landmark privacy case known as Katz v. United States, finding that the use of a stingray does require a warrant. But as of this writing, no cases challenging the use of stingrays have reached the Supreme Court, so this legal theory hasn’t been cemented just yet, as stingrays continue to be used in everyday law enforcement."
https://www.politico.com/magazine/story/2018/06/03/cyrus-farivar-book-excerpt-stingray-218588
The new state laws and federal policies came as a result of dogged activism by the ACLU and other privacy groups, which all stemmed from Rigmaiden’s case. After all, it was Rigmaiden who had initially reached out to Soghoian and presented him with a 200-page memo on a technology that few outside the government had known about. “It was the most well-researched memo I’d ever seen on this technology,” Soghoian later told WNYC. “Written by a guy rotting in jail.”
Now that lawyers know what to look for and how to challenge them, some of those efforts have been successful. Notably, in March 2016 a state appellate court in Maryland took local law enforcement to task, and ruled unequivocally: “We determine that cell phone users have an objectively reasonable expectation that their cell phones will not be used as real-time tracking devices through the direct and active interference of law enforcement.” The three-judge panel in the State of Maryland v. Andrews case also noted that such a non-disclosure agreement is “inimical to the constitutional principles we revere.”
In other words, judges now seem to be resoundingly echoing the 1967-era Supreme Court language—“reasonable expectation of privacy”—of a landmark privacy case known as Katz v. United States, finding that the use of a stingray does require a warrant. But as of this writing, no cases challenging the use of stingrays have reached the Supreme Court, so this legal theory hasn’t been cemented just yet, as stingrays continue to be used in everyday law enforcement."
https://www.politico.com/magazine/story/2018/06/03/cyrus-farivar-book-excerpt-stingray-218588