A provision in a will or trust agreement that provides that someone who sues to receive more from the estate or trust or overturn the governing document will lose any inheritance rights he or she has.  These clauses are not permissible in all instances or in all states. Section 2521 of the Pennsylvania Probate, Estates and Fiduciaries Code says that your no–contest clause will not be enforced if whomever is challenging your Will has probable cause to do so.