Mont. Code Ann. § 72-6-206

The provisions of 72-6-211 through 72-6-214 and 72-6-216 concerning beneficial ownership as between parties or as between parties and beneficiaries apply only to controversies between those persons and their creditors and other successors and do not apply to the right of those persons to payment as determined by the terms of the account. Sections 72-6-221 through 72-6-227 govern the liability and setoff rights of financial institutions that make payments pursuant to it.