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.
Hm, really? On my up-to-date iPhone 13 Mini, I have all of AMBER, Emergency, Public Safety, and Test alerts disabled. Seems like this would fall under at least one of those. I guess we'll find out :) I don't mind a text alert, but I'll be pretty pissed if it makes a bunch of noise.
At least for the ones sent in the Netherlands, if the iPhone is in silent mode, instead of making noises, it will vibrate strongly for a full minute or so.