Following on from the thread about what happens if you're out with a child - as somehow I doubt they would allow the dog in the ambulance...
What happens if you are taken ill or injured when out alone with a dog? It happened to me recently when I was hiking in a remote area with DDog, 2-3 hours drive away from the nearest person who could take him. I managed to get myself home by car, but wound up being admitted to hospital for surgery. If it had been a broken leg I wouldn't have been able to get back to the car, let alone home, and frankly I only drove because with the dog there was no other way to get home.
What happens in these circumstances? Behaviourally, he's not an easy dog, so I couldn't in good conscience ask a stranger to keep him safe for me in case something went wrong.