At 2:18 pm ET today, millions of people in America will get a text message that reads, "Presidential Alert.” The text is a test of FEMA’s Wireless Emergency Alerts System. If you click on the text, you’ll see the words: “THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed.” As we reported, this test is the evolution of long-standing national effort to create the perfect doomsday alert system. Some people, however, want to opt out.

Unfortunately, they can’t---officially. Though you can turn off Amber and other emergency alerts in iOS and Android, those settings won’t affect your ability to receive this test.

There is a workaround, though, if---like the people in New York who sued to try to block the test last week---you really, really don’t want to receive this message. FEMA says that the test will last approximately 30 minutes, so as one eagle-eyed Twitter user pointed out, you can just put your phone into Airplane mode from 2:18 pm ET to 2:48 pm ET and not have to see or hear the message come in. Voila.

You’ll also need to turn your TV off, because FEMA is broadcasting the test over the Emergency Broadcast System at the same time.

Even if you do opt out of the test today, understand that in a real emergency you won’t be able to because you won’t know ahead of time when the alert is coming. And that’s a good thing. After all, this alert is a test of an emergency system that is trying to help save your life.

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