Lu,
"During the low G condition lateral cyclic has little, if any, effect [on the helicopter fuselage] because the rotor thrust has been reduced."
To a beginning pilot the main point they're trying to make is that when the rotor on such a helicopter is unloaded, laterial cyclic will have nil effect on motion of the _helicopter_.
The difference between what you, and HeloTeacher and I are saying is between control of the helicopter, vs control of the rotor. The cyclic control is still intact--therefore it will still control the feathering angle of the individual blades and therefore the disc plane. The rotor will not cone, and therefore it will no 'flap back' with forward speed. But this is the only difference between the loaded and unloaded rotor system dynamics on their own. Because the rotor doesn't apply any force in the plane of the disc, and lift that is normally present perpendicular to this plane while in positive-g flight is not there, the rotor does not apply forces to the fuselage of the heli. Since we're talking about a teetering rotor, no moment from the rotor is applied to the rotor shaft. The difference between teetering heads and articulating heads with hinge offset or hinge spring is the reason why low/zero-g flight is so much more dangerous in a teetering rotor helicopter (B206, R22, UH-1, etc). I know that on at least one fully articulating helicopter the restiction is not 1g, but .5g. I imagine on some hingeless heads it's probably 0g.