I'm a Corbin Fisher subscriber, and I've never gotten any mail or unsolicited adverts. The address is just to verify that you are the authorized user of that credit card. I like them more often than not.
This is no longer true. Corbin Fisher collects (and saves) all the information you provide during enrollment (and all subsequent visits to the CF web sites) to use against you if they deem that you have infringed on any copyrighted material or trademarks (and not just CF owned materials). Specifically, on May 20, 2011 Corbin Fisher added the following to their Privacy Policy: (the "We" in the following paragraphs is Liberty Media Holdings which is the owner of the Corbin Fisher web sites.)
Added to Secton 3.1.1 - We also collect Your I.P. address and all of the personal information You provide to our billing providers.
Section 5.3 We will use any information You provide us with, actively or passively, in order to pursue You for intellectual property theft. If we deem the information to be useful to other parties seeking to bring you to justice for intellectual property infringement, we will provide your information to them or we may publish it.
Section 6.1.6 We specifically reserve the right to use any and all of your personally identifying information in order to protect our, or other companies, intellectual property rights. If we suspect that you have participated in copyright or trademark infringement, the we can and will use all information gathered about you in order to bring a lawsuit against you and to collect any judgment against you.
Although I know of no cases where this has happened the above section implies that if CF suspects you participated in any copyright or trademark infringement they reserve the right to provide you personal information (including your name, age, email address, credit card information, billing address, shipping address, IP address, guest IDs, geographic location and other session data) to other parties. Note that CF does not limit this to protection of CF copyrighted materials. In short, CF reserves the right to share your personal data with other organizations, such as the RIAA, MPAA, other porn studios. CF even states that they reserve the right to PUBLISH your personal information if they "deem the information useful to other parties seeking to seeking to bring you to justice for intellectual property infringement." I wonder what VISA would say about a vendor that states a willingness to publish customer credit card information.
Sorry for the long, barely on topic post. I too am CF subscriber and overall like their content; however, over the last year CF has pursued legal action against a large number of people that they have deemed to be copyright infringers (using torrents, etc). CF's willingness to share their subscriber's personal information with other copyright holders is at the very least a worry.