Utah Code § 4-5-402: Defenses.

No publisher, radio-broadcast licensee, or agency or medium for the dissemination of an advertisement, except the manufacturer, packer, distributor, or seller of the article to which a false advertisement relates, shall be liable under this section by reason of the dissemination of such false advertisement, unless he has refused, on the request of the department to furnish it, the name and post-office address of the manufacturer, packer, distributor, seller, or advertising agency, residing in the state of Utah who caused him to disseminate such advertisement.