I hear this all the time around here and the same thing on motorcycle forums and it just sounds crazy. On most bikes your arms and your torso make an A. You might have your elbows bent but you still carry plenty of weight on your hands. I've never seen anyone ride no-hands without sitting up. The only way you'd keep weight off the bars and your hands still on, is by sticking yourself halfway through a dead lift for hours. I would wager no one actually does this, except when on the attack over obstacles, not riding up the street.