From the article:
When we went to our seats, the wait staff let us know that despite the fact that the previews were playing, we wouldn’t know until the movie actually started whether we could see the film or not. If it didn’t work, the screen would just turn black. Luckily, the film went through without a hitch.
Yeah this was nonsense. Like it is mandated to have a TV always on to receive such emergency broadcasts. Same thing can happen to someone not having or not using a TV