I think it's an excellent idea. I called an ambulance for a friend who'd had a seizure and bumped his head quite badly on the way down, and this wasn't a million miles away from what happened. I got a call back to see if he was recovering OK, which is was, and they gave me a few numbers I could call for a cab. BUT you see, I had to pay, so I want this to be instigated so that next time I get a FREE cab (joking).