It seems that law enforcement trumps privacy. Unfortunately, this isn't surprising. I doubt it will hold up in court but as always its better to ask forgiveness than ask permission.
The Federal Bureau of Investigation is taking the position that court warrants are not required when deploying cell-site simulators in public places. Nicknamed "stingrays," the devices are decoy cell towers that capture locations and identities of mobile phone users and can intercept calls and texts.