I've never been hit by a car when riding on the sidewalk (which I rarely ever do anyway), but I did hit someone who was riding on the sidewalk.

About 12 years ago. I pulled up to the intersection where there was a stop sign. Waited for traffic to clear, and began to pull out and BAM! Coming off the sidewalk from my right side a bike must have been going 20+ mph. He was traveling fast enough that when I glanced down the sidewalk looking for pedestrians, he was far enough away to be out of my field of view due to some shrubbery on the corner. Plus, riding contrary to the flow of traffic gave me much less time to see him once he became visible. Thankfully, the rider was unhurt and the only damage was a few scratches to my car. He cursed me out, hopped on his bike and blasted back down the sidewalk before I could even collect my thoughts and get out of the car.

Also a friend of mine was killed about a month ago after being struck by a car while riding his bike. There were multiple factors that led to the accident, but one of the ingredients was that he was riding on the sidewalk. Perhaps if Tommy had been in the street where he would have been more visible it would have been enough to prevent the tragedy? One can only speculate. I am pretty sure he was riding down the sidewalk because it was a farily busy street and he figured it was safer.

Sure these are anecdotal examples, but they are enough to convince me it's safer to be in the street.