This is a violation of CAN-SPAM. Feel free to rightfully flag violators as spam.
Clarifying that to submit a valid opt-out request, a recipient cannot be required to pay a fee, provide information other than his or her email address and opt-out preferences, or take any other steps other than sending a reply email message or visiting a single page on an Internet website.
Clarifying that to submit a valid opt-out request, a recipient cannot be required to pay a fee, provide information other than his or her email address and opt-out preferences, or take any other steps other than sending a reply email message or visiting a single page on an Internet website.
http://en.wikipedia.org/wiki/CAN-SPAM_Act_of_2003