The option mostly applies outside of Canada. We get only one type of alert and thats the highest level so we would recieve it no matter what options you set. For the majority you can't opt out of the alert.
Nobody is interfering with your phone, as mentioned in Canada ALL alerts are sent out as Presidental Alerts which you cannot block. In other parts of the world (such as the US) an Amber Alert is sent out as an Amber Alert a Tornado Alert would be sent out as a Severe Alert which means you can disable those.
So unless Alert Ready/CRTC change the alerts to how they function you'll never be able to block them in Canada. You can take a look at their website: https://www.alertready.ca/ and send them a message and hope that they send the alerts as they are supposed to (like in the US)
As others have mentioned theres no way to opt-out of getting alerts but there are ways to avoid getting the sound.
- Have your phone in vibrate and it'll only vibrate when you get an emergency alert.
- Turn your phone off means that you won't get the alert entirely.
- Put your phone in airplane mode does the same thing as turning your phone off.
- Having your phone in Do Not Disturb may work? It works for some but not others, your mileage will vary with this one.
I don't know of any other way to not get the sound when you get an emergency alert. I personally have my phone on vibrate and I've never gotten the sound when an alert comes.