You may just be unconscious, not completely dead.
With apologies, I can't help but think of
The Princess Bride:
Inigo Montoya: He's dead. He can't talk.
Miracle Max: Whoo-hoo-hoo, look who knows so much. It just so happens that your friend here is only MOSTLY dead. There's a big difference between mostly dead and all dead. Mostly dead is slightly alive. With all dead, well, with all dead there's usually only one thing you can do.
Inigo Montoya: What's that?
Miracle Max: Go through his clothes and look for loose change.
You are right, of course. It certainly would be useful to have ID if I was alive but unresponsive. I would think my wallet would be on me but that's not a certainty I suppose.