That is strange. Apparently in Urbana property owners are only required to shovel their sidewalks in specific parts of town: http://www.urbanaillinois.us/businesses/sidewalk-snow-removal

Of course it would be nice if everyone would shovel their walks. I wonder if this program would actually disincentivize homeowners on the marked streets from shoveling. Why should I shovel my walk if someone else has volunteered to do so? (A hypothetical; my street has no sidewalks.)