Riding anything at speed (i.e., > 3mph or so - walking speed) on a sidewalk is not only an asshole move, it's dangerous to everyone involved, including most especially the rider. You are just begging to have someone walk into you, get clothes lined by a leash, have a dog or kid jump into you, get hit by a car pulling out and not expecting high speed on a side walk, etc, etc etc.

Better than biking in a door zone, I guess. Maybe. But a super bad idea.

So, of course, common as dirt. Even more of a reason that it's dangerous.