I'll correct myself - You can rotate the on knob to the position where the radio would appear to be on. For a person with a radio that has been inhibbited, it will appears as it is dead. You can push buttons all you want, nothing will happen. The system controller can signal (or put the user ID in the datastream) that will allow the radio to come back alive.
We have XTS5K's at our ambulance service and when a radio get's stunned, it's just like there is no battery attached to it. Once the user ID is placed back in the datastream, then it will come alive.