[mass55th]

That would be alot of fun if you've got to get to the Emergency Room in a hurry. And what happens if the system malfunctions? Who will pay for the damages if a false reading occurs? Hmm. Sounds like there could be a job opening for John Edwards after his Senate term expires.

[swarthyguy]

Fixed by eventually tying it in to a DNA type identity breath and match test. Based on your specifics and anybody else who uses the car. In an unusual situation, the legal aspects could get as sticky as a spilt Daiquiri.