Speaking of blades being tied-down; I remember an occasion, quite a few years ago now, when a pilot started the first engine of a 212 and got it to flight idle before he realised the main rotor was not turning. Not being able to diagnose the problem he shut-down, got out and then noticed that the tail rotor was still tied-down. He then promptly removed the tie-down and proceeded with the flight. No discrepacies with the drive-train were found after his return.
So yes, the drive train is very robust - but as many have commented here - gently does it when turning the main rotor by the tail rotor.