I don't know if it's an urban legend or not, but that doesn't really matter. I read in an email a while back about an EMT with a good idea. Often times car accident victims have cell phones that they find on the scene. If the victim is unable to communicate, then they can't tell the EMTs who to call, and the EMTs wouldn't know who to dial in the cell phone contact list. I think the solution is kind of neat.
Pick your In Case of Emergency person and list them in your contacts as ICE (then name). For example, when my hubby calls me it comes up ICE, Mark, husband. Hopefully I'll never be in the position to need this, and who knows if the EMTs would have heard of it, but it sure doesn't hurt to give it a try, especially if we spread the word.