Mont. Code Ann. § 46-4-404

Except for gross negligence or willful or wanton misconduct, there is no cause of action against a service provider, landlord, or custodian or their officers, employees, or agents or other nongovernmental person for injury or damage caused in furnishing facilities or assistance under the order or against a service provider or its officers, employees, or agents for providing the law enforcement agency with information received from the operation of the pen register or trap and trace device. The immunity provided by this section does not extend to any governmental agency, law enforcement agent, or prosecutor.