I've been on a mission to unsubscribe from a few mailing lists that I opted into at one point or the other. It's an annoying process most of the time, and of course you're never sure if your request is going to be honored. Some people might just click "Report Spam" on these emails, but since I chose to receive them, I feel that wouldn't be fair. You run across a lot of odd things when you are doing this. For example, here were the instructions I found on a piece of mail I tried to unsubscribe from this morning.
You can choose which specific emails you'd like to receive from [ACME Corp] by checking the boxes below to opt-out when you do NOT want to receive that type of email. We recommend opting-in for all email since they keep you informed, and help you enjoy ... our site
I'm not sure what the rule is for allowing people to opt-out of your email, but I wonder if it has a part about making the instructions clear. I had to read that two times to figure out whether I checked the boxes to unsubscribe or if I left them blank to unsubscribe. I checked the boxes, hopefully I got it right.