Once you join, you can't get out of it. I'm trying to cancel my account, but I must provide a password. I signed in with Facebook, so I don't have a password. There's no option to cancel your account with Facebook. Then I clicked on the Change Password option. I must insert my "old password". I DON'T HAVE A PASSWORD. I asked for help and RewardsCentral never replied.
So, I tried unsubscribing to their e-mail, but I can't unsubscribe to all of their e-mails... if you have an account, you must receive at least their main e-mails.
So, I'm TRAPPED!
My advice is: DON'T SIGN UP!