I'm a nobody, but I imagine the feds or spooks would never use anything like that on someone they have physical access on. If the target is in their jurisdiction or a blacksite and it's that important, a lead pipe is easier.
IF they can decrypt stuff, they'll only use it when it's has an actual benefit beyond a conviction and the keys are truly inaccessible. (e.g., person is dead, the keys are in an enemy state HSM, etc.)
IF they can decrypt stuff, they'll only use it when it's has an actual benefit beyond a conviction and the keys are truly inaccessible. (e.g., person is dead, the keys are in an enemy state HSM, etc.)