0g in free fall, little bit of negative g moves things.
HC, I agree: detach the rotors, and you will briefly free fall: there will be weightlessness, which then rapidly (~5s later) returns to normal conditions at the terminal velocity (c.f. AF447).
However, you're not blowing the blades off to experience this, you're pitching them down.
If your clipboard drifts up off a flat surface in the absence of any lateral acceleration to make it bounce off a projecting lip, I agree: that's (briefly) real negative g, with g~-0.0X, where X~1-5. Things "drift" at 0.0Xg; they "fly around" at -0.Xg, and at -Xg they hurt you.
I find this a very interesting discussion - there seems possibly to be a transatlantic polarization developing about old Isaac's ideas, and how air interacts with whirling blades, and that's definitely not based in physical reality. If it's not all just a mix of semantics, cultural difference, sloppy description and misunderstandings, then getting to the bottom of these differences will surely lead to greater awareness of the energetic perils of rotary wing flight, and make everyone's life safer.