Earlier quoted context omitted.
> It also is ineffective at blocking audio If you turn your phone off and immediately put it in a Faraday bag, how would it receive a remote command to turn on and start recording audio?
That's implying that it is actually off and not just pretending to be off, and that it requires a command to start recording instead of just constantly recording and only uploading when commanded to
Of course this applies whether it appears to have a removable "battery" or not.