The FBI set the first (and second!) rules of Stingray Club: DO NOT TALK ABOUT STINGRAY CLUB. Law enforcement agencies seeking to acquire cell tower spoofing tech were forced to sign a nondisclosure agreement forbidding them from disclosing details on the devices to defendants, judges, the general public… sometimes even prosecutors.
A new wave of parallel construction washed over the land, distancing defendants from the source of evidence used against them. Pen register orders — used to cover the tracks of Stingray searches — started appearing en masse, as though it was 1979 all over again. If curious lawyers and/or judges started sniffing around, agencies were instructed to let accused criminals roam free rather than expose details about Stingray devices. According to the FBI, public safety would be irreparably damaged if Stingray details were exposed. Apparently the return of dangerous criminals to the street poses no harm to the public.