[DoughnutHole]

Emergency alerts are the sort of thing that you don't want to be opt-in, simply because most people aren't proactive. It's not great for grandma to drown because she didn't know she had to subscribe to tsunami warnings on a specific website. Apps are also not ideal if you have to opt in and download them.

Traditional emergency alerts would take over all live media in the area, ie interrupt TV and radio broadcasts. In high risk towns like in tornado country they have literal klaxons that blare the warning to anyone within earshot.

As much flak as it got, the UK emergency alert system is a pretty good solution - collaborate with cell networks and the developers of the major phone OS's to push a notification to anyone in the at-risk area. It'll never truly be universal, but 80% of phones were capable of receiving the last test, and of those 7% didn't receive it. Honestly that's a much better reach that we ever would have had with radio and TV alerts.

[em-bee]

well, yes of course, but if it is not opt-in then apps are out of the question anyways, because you can't have apps preinstalled on every phone. that just won't work.

there are different levels of alerts. obviously the really serious ones should be pushed as you say, but lesser ones, or serious ones but for people who are not in the region should be opt-in. there is no need for me to get tornado warnings from the area where my grandma lives, but i may want to subscribe anyways because i want to see her safe and maybe i am planning to visit. so it does make sense to publish alerts on channels that anyone can follow as they need.

[MandieD]

That's the nice thing about NINA in Germany - I can pick very specific geographic areas to get alerts for, like the town I live in, the city I work in, the rural area my in-laws live in. If you're willing to spend a few minutes, you can adjust what level of warnings you care to receive, and how they behave.