I actually had a driver yell at me "get in the road" because I ride one half block of my commute on the sidewalk to avoid where the trolley tracks join the road. This was in the waterfront entertainment district at 7 in the morning--the sidewalk is 15' wide and there are no pedestrians (or joggers!) for at least a mile.

Not everything is cut-and-dry and don't assume that a sidewalk cyclist is a bad cyclist.