We can’t find a current reference for this one, so if you do – let us know!
Maybe they’re trying to keep skaters off the sidewalk in busy shopping areas?
This is an Auburn, AL municipal law. Section 9.08.010 Spitting. It is unlawful for any person to spit upon the sidewalks, or upon the floors of places of worship, buses, public halls, theaters or other public places. (Ord. 63A 3-12, 1977)