I'll say that in my local AHJ - the code is interpreted as the system must stop making noise. Muting is acceptable. Muting in a way that leaves one mic hot is also acceptable.
HOWEVER - none of these systems are required to be able to make emergency evacuation announcements or meet intelligibility requirements.
That doesn't mean we are doing it right, it's just how our guys interpret.
I have made a strong argument for a single hot mic, and our fire and building inspectors agree that having an announcement option in an emergency is better than no option.
That's why it is so important to check with the local AHJ. I have had AHJs require that all the amps be powered off and they had to see it function properly and other AHJs required that the system be completely muted with some verifying the muting and others just assuming it would be taken care of. On the other hand, some AHJs acted like they had no idea what I was talking about when I asked about what we had to do.