My mom knew a guy who was mugged and beaten to unconsciousness after a football game, or baseball game, or something similar. Some people saw him unconscious on the ground and found his phone and used it to call his home and tell them what happened. (I assume they called 9-1-1 also, donno whether or not they used his phone to do it)
I tell ya, these phones are incredible things. Check out a book called "The World Is Flat" (forget the author), it's really interesting. It's about how pretty much anyone can instantly get in contact with pretty much anyone else, anywhere, at any time.