so despiteall that, when you are using the prefs screen and turn the input volume theway cown, it should not register any input right? Thenwhy does it? thas not nothing.
A microphone is a mechanical device, so it will always produce output regardless of what your volume settings may be.
To get technical, you are controlling the gain of the volume of the stage after the microphone. So in the real world the microphone should always show input unless physically disconnected. Computer manufacturers don't follow any standard practices it seems, so you may see it both ways.
Sounds like a bug. I can't reproduce it on my Air, and it appears other commenters have difficulty reproducing it as well. The OP/commenters experiencing the issue should probably file a Radar.
