There was a flurry of news a few weeks ago, about the FBI having to cut back on use of the "Stingray" cellular monitoring hardware.
My question is "What was the FBI using it for before"? There were some news stories about the Feds having Stingray-equipped aircraft flying around to monitor "everything" in the cellular world, and lurid warnings about how cellphones could/would be used to track us all from cradle to grave. AFAIK, none of it was ever proven, but my information may be outdated.
Bill