We need a way to disable the microphone so it cannot be re-enabled, at least by an unprivileged user. And preferably via the command line, so it can be scripted. On some Macs, we've been able to remove kexts, but on others, that also disables speakers, and we'd like to keep sound output.
I think the only way you could do this is chmod and or chown the Preferences app, of course this can be done via the command line.
In addition you could build an Apple Script to Mute the Microphone