This was the most surprising issue of the downtime. Rogers had just enough layers lit up for 9-1-1 calls to be attempted (to only fail) on its completely dark network that cell phones didn't/wouldn't failover that 9-1-1 call to the other mobile networks that were up.
It's all network traffic, and the network was DOWN. (It's not like when we had physical circuits, and if one part wasn't working it could be offlined without affecting the others).
911 traffic would have the highest priority, but without actual traffic flowing it's a ticket to nowhere. I'm guessing the cell towers had power, and likely the call routing software is programmed to drop calls to handle 911 requests, but still had no network to send the calls through.
As a user, I think you can disable your carrier (or, worst comes to worse, pop out your SIM card) to get picked up by another network -- but that isn't most people's thought process in an emergency.
Would be nice to see if this changes the approach at all -- example, If no network -> don't advertise or talk to our phones -> allows them to possibly roam or use other nets
I suspect if you popped the SIM out, it would try any of the 3 providers available (in Toronto anyway), and dunno how the device chooses which. If it chose Rogers (strongest signal?), it would also fail to go through and you might be unable to get a 9-1-1 call in until you run in the right direction.
But few carry around a 'trombone' for emergencies, and I'd need something sharp to get my case off.
But my blame is on the cellular phone: A 9-1-1 call that makes it to the tower and no further shouldn't be counted as a success by the phone.