i have no problem letting the airline know who i am. i have no problem with them making sure that the person on the ticket is the one flying, and that person is actually on the plane.
if the worst happen and the airplane crash, i would not want to put myloved ones through the gruesome process of waiting for someone to find one of my teeth for identification. i would want the airline to tell them without a shadow of a doubt that i was indeed on the aircraft.