SAN FRANCISCO — Charles Dell’Ario can’t say he wasn’t warned.

Before appearing at the California Supreme Court last June, Dell’Ario tested out his arguments about franchisor liability in a moot court at Golden Gate University School of Law. “Counsel, here’s what really concerns me about your position,” said professor Myron Moskovitz, playing the role of one of the justices. “If we rule in your favor, does that mean virtually all the franchisees in California—McDonald’s, Domino’s, Burger King, Wendy’s—they all become agents of the franchisor for all purposes?”