The selling of goods or services on someone else's property is prohibited. The term "curbstoning" shall mean the offering for sale of motor vehicles, mobile homes, travel trailers, utility trailers, campers, boats, or personal property of any kind, on public or private real property, except as specifically authorized by law, and notwithstanding permission being given to the vendor by the owner of such real property. This definition shall not apply to individuals offering for sale such items on their own real property, or to vendors properly licensed for such sales.