ShyTorque,
If the centering device you refer to is the tail rotor spring bias unit, then I think we are still waiting for it to be fitted (along with a torque meter/anticipators/Makila engines!). As you have said, the simulator is an invaluable tool to get you thinking about tail rotor malfunctions. I'm pretty sure that if it happens for real however, the 'What the f...' factor will precede the 'THROTTLES!' call by some distance!