I got an email that almost looked like it wasn't spam in my inbox, and I opened it. So like a lot of things they have a link you click if you don't want to receive email from them anymore which normally puts you on a few other mailing lists of people that probably pay them. So I take this link they give me which includes my email in a GET request, and I stuck their email in.
ex.
http://gkiregusn.turtlehurdle.com/s/u.cgi?e=my!email.com&l=grsyahooopeners005
I replaced with
http://gkiregusn.turtlehurdle.com/s/u.cgi?e=their!email.com&l=grsyahooopeners005

Let's say they actually gave a valid address to reply to, do you think that this would put them on the extra mailing lists that you would normally get put on for trying to unsubscribe, or do you think it does nothing?