I have trained engineers for engine runs and emergencies in the aircraft and in the sim but never for rotors running checks.
If the aircraft is tied down, that is one thing but just having the controls frictioned or even locked is potentially hazardous. Allowing control movements would seem to automatically require a pilot.
The fact that no hyd checks are allowed seems to indicate that someone has at least thought through the potential for the inadvertent airborne scenario as do the extra limitations for wheeled aircraft due to the propensity for ground resonance.