Placing tacks on a sidewalk is considered a public nuisance.
845.010. Public Nuisances Affecting Peace, Safety and General Welfare. The following are declared to be nuisances affecting public peace, safety and general welfare: 1. interfering with, obstructing or rendering dangerous for passage, a public highway or right-of-way, or waters used by the public; 2. leaving or displaying anything for sale on public or private property,…