I submitted a report. I am wondering if iMovie just works on the metadata, not on the file, so it is a problem of the architecture of the software rather than a missing option.
But it is really a pain. If I need to shoot some interviews I like to cut out the question and leave the reply. I have a lot of footage that I can trim and trash parts I have no use for to make the editing faster and save HD space.
I could use the old iMovie 11 (although I wonder if it modifies the quality of the original clip by converting it in a different format) but it is such a slower process and 2 steps instead of one.
IMovie 10 is great at showing the sound waveform so I can see with my eyes the parts where there is silence no sound during an interview, making the selection / rejection of those parts easy.
too bad I can not just get rid of them.