I don't know how other MBs are, but on a 108/109/111/112, if improper torque caused warping of rotors, the hub would also become warped. They are bolted together quite well.

Also, if improper torque caused rotor warping, wouldn't it also cause the WHEEL ITSELF to warp as well? They're mated flat and tight against each other with a LOT of force. If one warps, the other will have to warp as well.