An off-duty, out-of-uniform police officer and his son purchased some food from a convenience store and were still in the parking lot when a carload of teenagers became rowdy. When the officer went to speak to them, the teenagers assaulted him. The officer shouted to his son to get the convenience store clerk to call for help. The son entered the store, told the clerk that a police officer needed help, and instructed the clerk to call the police. He returned 30 seconds later and repeated the request, urging the clerk to say it was a Code 13. The son claimed that the clerk laughed at him and refused to do it. The policeman sued the store for the injuries that the teenagers caused. This case primarily deals with ____.