Mont. Code Ann. § 46-15-325

The fact that a witness's name is on a list furnished pursuant to this part but the witness does not testify or that a matter contained in a pretrial notice is not raised may not be commented upon at trial unless the court, on motion of a party, allows comment after finding that the inclusion of the witness's name or the pretrial notice constituted an abuse of the applicable disclosure requirement or that other good cause is shown.