I accidently ran into this awhile back-
I was doing CPR on a guy way up in the woods on a mountaintop, waiting on the first response crew/ambulance to show up (basicly find us ). When the victim was finally loaded up on the stokes to be carried out, one of the ambulance crew collected all the items laying on the ground that was on/near the victim...includeing my cell phone. At the time, I never noticed it wasent in my pocket- when i discovered it missing, I knew it was either with the victims personal belongings, or still with the ambulance crew...this was about 2 hours after the incident...before I could call anyone, there was a knock at the door.
one of the first responders was standing there, holding my phone. I asked him why he didnt call the first entry-"HOME", or any of the others...like, mother and father, work, ect...
he said it was much easier to just call the cell provider and get my physical address, since he wasent sure if I was the deceased or not and the family hadent been notified. Since physical address`s are a basic part of the contrat to owning a paid phone (not a one time use phone, pay as you go)- it was a simple matter for him....BUT, he said with the prevalence of the cheap phones, its better to put the first number-after 911- as "emergency contact"