Folks who peddle their wares from door to door have a constitutional right to annoy you. “For over 50 years, the Court has invalidated restrictions on door-to-door canvassing,” Justice John Paul Stevens wrote in a landmark 2002 Supreme Court decision. The right to solicit door to door is protected under the First Amendment as free speech. Free speech covers sales communication too.
Door-to-door salespeople take away your employees’ time from their normal duties. They disrupt your business. Short of rudeness or unpleasantness, how can you stop this from happening?
There are two lawful ways, the courts say. The first approach is to tell the salesperson “We’re not interested.” Of course, good luck with that! Any salesperson worth his or her salt will view such a statement as an invitation to begin a 30-minute conversation.
The other method was highlighted by Justice Stevens. “The posting of ‘No Solicitation’ signs,” he wrote, coupled with the “unquestioned right to refuse to engage in conversation with unwelcome visitors, provides ample protection for the unwilling listener.”
In other words, anyone who does not want to talk to door-to-door canvassers has two options: tell them no or else put up a “No Soliciting” sign.
Municipal governments often pass ordinances that address door-to-door selling. Typically the ordinances will impose a permitting requirement, and part of the paperwork obligates the salesperson to promise to obey “No Soliciting” signs. Salespeople who do not want to have their permit revoked will pay attention to such signs.
What better way for a salesperson to “get a foot in the door” (so to speak) than to simply walk inside your business establishment and insist on speaking with someone? The First Amendment hamstrings government efforts to ban this outright. The most effective countermeasure is to hang up a prominent, this-means-business, absolutely-not-kidding-around “No Soliciting” sign.
 Watchtower Bible and Tract Society v. Village of Stratton, U.S. Supreme Court decision dated June 17, 2002.
 E.g., “Violations of Solicitor Regulations,” Official government website of Fairfax County, Virginia, https://www.fairfaxcounty.gov/police/stations/reston/rib2013/solicitorviolation.htm, accessed on June 3, 2015.