It's also why you can possibly make an emergency call when your phone has no bars of signal displayed and won't make a regular call.

It will connect an emergency call even if the quality is well below the standards for a normal voice call.

Yes, that is exactly what happened back then: it was in the ratified spec. I can't believe that newer systems would be any different.

I've explicitly dialed 112 (when I actually had a reason to call 911) just to see if it worked. It worked perfectly fine.

Can confirm 999 also works in Canada after an embarrassing pocket dial in which I had to explain to the authorities I was not being threatened or under duress and it was in fact just an accident.

What about 01189998819991197253?

This is incorrect. When I worked on LTE networks, I did work on a few problems with VoLTE based 911 service, although I didn't specialize in 911 services.

In many ways, something like an LTE tower doesn't really know what a phone call is. It just looks like packet data. So there are several fields in the signalling, that indicate that a request is related to an emergency, which should have emergency handling. This can include things like dropping other lower priority traffic, prioritizing the packets themselves on the network, etc.

But the other interesting thing is in VoLTE, you actually do a new IP assignment (to an sos PDN) specifically for the emergency call, so you have a sort of new registration to the network. This allows you to make an emergency call on any network that is available. Although scanning for an available network can take some time, so you'll likely use your own carrier if they're currently available.

Note: I've been out of the industry a few years now, and specific to emergency calls only have knowledge specific to LTE and UMTS.