How Can I Change Him?
From Q and A in Child Discipline By James Dobson (1976)

Many parents do not like to punish or correct their children in public places where their discipline is observed by critical onlookers. They'll enforce good behavior at home, but the child is "safe" when unfamiliar adults are around. In this situation, it is easy to see what the child has observed. He has learned that public facilities are a sanctuary where he can act any way he wishes. His parents are in a corner because of their self-imposed restriction. The remedy for this situation is simple: when little Roger decides to disobey in public, take him by the arm and march him out of the presence of your observers. Then respond as you would at home. Roger will then learn that the same rules apply everywhere, and that the sanctuaries are not really so safe after all.