Section 2-517
A provision in a will purporting to penalize an interested person for contesting the will or instituting other proceedings relating to the estate is enforceable.
Massachusetts comment
The Committee recommends against UPC Section 2-517, which would make in terrorem clauses unenforceable if probable cause exists for instituting proceedings, as it prefers to continue present Massachusetts law which permits enforcement of in terrorem clauses. See 2 Newhall on Settlement of Massachusetts Estates (4th Ed.) § 348 and Old Colony Trust Company v. Wolfman, 311 Mass. 614 (1942).