The US alert system has severity levels. I think there are amber alerts (child abduction), two "regular" severity levels, and then "presidential alerts" (meant

The US alert system has severity levels. I think there are amber alerts (child abduction), two "regular" severity levels, and then "presidential alerts" (meant for "the aliens have invaded" or "nukes inbound"). By law, presidential alerts cannot be disabled - but users can still turn the whole feature off. I'd assume that within the US, only the president or a high-ranking delegate is authorized to send these alerts, preserving the ability for these to actually work even if local authorities decide to flood people with bullshit on the lower levels. Canada, in its infinite wisdom, has decided that it really wants people to not turn off Amber alerts (frequently sent in the middle of the night), so of course they use the code for presidential alerts to send them... Part of the reason for the bad UX of these alerts is that they're legally regulated, and the laws are, or at least were overly specific, often preventing better solutions like letting the users configure the alarm behavior (i.e. you have to turn amber alerts off if you don't want to be woken up by them, rather than turning them into a regular notification). And since it's a regulated topic, even the improvements that would be possible would require legal review, i.e. once the feature is "good enough", few developers want to touch it and subject themselves to bureaucracy hell. This system is based on cell broadcast - cell towers can send a message that will be received by all phones, without having to send it to each phone individually. The messages have channel numbers, and a set of channels are reserved for this use and most modern phones will display messages sent with those channels as alerts. That's also why e.g. Canada can seamlessly use (and abuse) the system originally designed for the US. I think severity levels are the saving grace of any overused alerting system. Swiss severe weather alerts also have severity levels, and while the default in some of the alerting apps is excessively sensitive (notifying for rain or wind that does not pose meaningful risk unless you're out hiking), it's very clear that you can just raise the threshold rather than opt out.