Using the Big Gulp as an example, yes, the California legislature would have to pass a law outlawing Big Gulps and specifying that enforcement of the law would fall to private citizens, who were empowered to bring a lawsuit against the 7-11 for providing Big Gulps. I used that example because conceivably a government could decide that Big Gulps were immoral because they hastened people's death. Mayor Bloomberg in NYC once floated the idea of banning sugary sodas for that very reason.