Is a Penalty Clause in an Arizona Will Valid?

Question:  My parents’ wills contain a clause that says that if anybody challenges the will in court the challenger gets $1.  Is that clause enforceable in Arizona?

Answer:  No.  Arizona Revised Statutes Section 14-2517 states, “A provision in a will purporting to penalize an interested person for contesting the will or instituting other proceedings relating to the estate is unenforceable if probable cause exists for that action.”