As I said above it is all in where you keep the phone. A pocket or phone holster is safe. If you store it in your butt there is a chance you might join the rainbow mafia depending on if you use the vibrate ringer function. It does add to your prison cred tho since you can smuggle in phones for other inmates.
Referenced on “Two and a Half Men”: Evelyn: “ At the autopsy, the phone was found on Vibrate”.