I saw this one too, and it's an interesting point to consider. I would imagine those people's phones would mostly already be usually concealed, because e.g. an amber or a weather alert with similar effects and consequences could come in at any time.
It's called a roving bug and dates back to at least the mid 2000's https://www.cnet.com/news/privacy/fbi-taps-cell-phone-mic-as...
Here's a bit more information for you, it should help with the fear-mongering bs.
> https://www.reuters.com/fact-check/out-of-coverage-switched-...