Every single character in The Pigman lies or deceives others at some point. John is a chronic liar, especially to his teachers and parents; Lorraine regularly lies to her mother; Mr. Pignati lies about his wife being in California; and Norton and Dennis are thieves. What is the point of all this lying? Can lying serve as a form of self-protection or self-preservation? If so, is it always wrong? Why do these characters lie so much? What does this imply about the possibility of honest communication?
Considering their role models, John's and Lorraine's habitual lying is not surprising.
Deception, for John, functions as a coping mechanism, a buffer between himself and the harsh realities of the world.