No, you may not. Under what exact circumstances the police may or may not is more dicey, but not too relevant to this case.
Stingrays are not collecting voice data, but metadata. More like a pen register than a phone line tap, but legally those require
The real truth is we don't have any real legal precedent on whether these are legal with or without warrants or not, as they and their workings have been systematically hidden from the courts. The FBI has been confiscating both the hardware and all details about them whenever people discover local law enforcement has been using them, sometimes in defiance of local judicial rulings.