Mich. Comp. Laws § 445.2506

Sec. 6. (1) An e-mail service provider may design its software so that a sender of unsolicited commercial e-mail is given notice of the requirements of this act each time the sender requests delivery of e-mail. The existence of such software shall constitute actual notice to the sender of the requirements of this act. (2) An e-mail service provider that designs and implements a dispute resolution process for a sender who believes the sender's e-mail message has been improperly blocked, and makes contact information accessible on its website, is not liable under this act for blocking the receipt or transmission of the e-mail.