I was headed for Portland, Oregon once but accidentally reserved an Avis car in Portland, Maine. Got to Portland, OR and they had no reservation for me, obviously, but fixed me up with a car and sent me on my way.

Two weeks later I received a bill from Avis for $3,000. The Avis office at Portland, Maine had put my name on a car. Some woman drove off in it and promptly wrecked it. They had me as the renter of record although I was on the other side of the country at the time. The Avis bureaucracy was completely ridiculous and it took weeks to convince they I was not responsible.