"On GrapheneOS, you can fully disable emergency alerts in Settings → Safety emergency → Wireless emergency alerts since we add a toggle for Presidential alerts.

The naming of the alert types varies based on country which is determined by the carrier’s country code, not language.

In Canada, the government sends every alert as a presidential alert instead of using the separate categories for extreme threats, severe threats and AMBER alerts. They do this to prevent disabling any of the alerts on normal operating systems and it’s why we added this feature.

That also means every alert in Canada has a siren.

Many of the more severe alerts have been false positives:

https://www.nytimes.com/2018/01/13/us/hawaii-missile.html https://www.preventionweb.net/news/canada-fallout-false-nuclear-alarm

Most AMBER alerts are custody battles or false alerts.

On GrapheneOS, it’s up to you if you want this feature enabled." - As posted by the official GrapheneOS mastodon