Think about this...

Take any smart phone. No SIM card. Connect it to someone's wifi network, like a coffee shop. Now you can abuse 911 world wide in a completely untraceable manner.

What can possibly be done to prevent this that won't screw people desperately in need of help? It doesn't matter if your government is responsible for a town of 100 people or a country of 1.2 billion. It can't put an owner to each of the billions of smart phones floating around and that's not going to change any time soon.