You'd be surprised with what drunk people will do! I had a friend that used to ride around Vancouver on a Honda scooter back in the 80's. He'd lock his helmet to the bike with his chain. One night he got back to his machine to find his helmet full of piss!
He (obviously) refused to wear his helmet home, and got pulled over by a cop. When he told the cop what had happened the cop laughed his ass off and let him go.
Now I don't think it's too much of a stretch to go from whizzing in a helmet to whizzing in a gas tank...