I'd also add that in many cases, riding on the sidewalk is illegal. It doesn't bother me when I see little kids doing it, but if you're a grownup you should be riding on the street, with traffic, in accordance with traffic law.
When I still lived in a small rural "micropolitan" area before moving to Akron a few years back, I was a road rider and belonged to a local bike club. There is no way they would have tolerated members riding on the sidewalk, and they stressed heavily that bikes are legally regarded as vehicles and have to obey the same rules.
I've since given it up, since I live in a high traffic suburb of Akron and being deaf, can't hear oncoming traffic. This wasn't a big deal on rural back roads, but now that there's a lot more traffic around me, it makes me nervous.