Mo. Rev. Stat. § 369.211
Any association doing a safe deposit business may enter into a lease under which a safe deposit box is rented in the names of two or more persons, whether residents or nonresidents of this state, as joint renters. If the lease provides that one or more of such persons, or the survivor thereof, has access and entry to the box and the right to remove the contents whether the other renter or renters are living, mentally incapacitated or dead, the association so renting the box, or upon the premises of which the box is located, shall not be liable for the removal of any of the contents of the box by the survivors thereof. No presumption of ownership of the contents of any such box shall be deemed to be created by the rental contract.
§ 369.211, RSMo
Effective 7/6/1994