It just means the children are not to go door to door selling things by themselves. It is a safety precaution. Mom & Dad can sell the stuff to whomever they want. They just don't want the kids going door to door like we did back when we were kids.
Starting next year, since we already signed the contract for this year, the board says no door to door sales. I never really considered the catalog sale a door to door thing, as parents and family ususally contact people they know. I am waiting for an answer from the "power that be" as to what would be considered. Any suggestions?