Important to note that not all phones are compatible with the Ready Alert system. If you have a compatible device, it must be connected to an LTE network when the alert is sent, and have the Cell/Mobile Broadcast function enabled (I think it is enabled by default, but it can be disabled)
I received the alert on the Fido (aka Rogers) network.
My brother and I have the exact same phone bought at the exact same time on the exact same network and I know I never touched cell/mobile broadcast and I kinda doubt he did but I got it and he didn't. As VHF said though, I don't think it's as needed now.