I addressed it in my post a few pages back. Re printing the pertinent part below from the post in italics, and added to it..
The difference is, as appraisers we pay the MLS for access, and since we join as an appraiser, they are aware we use MLS data in appraisal reports. I assume they allow us to do that knowing their own self interest is served by appraisers submitting reports which is part of the process for borrowers loan.
If I were to use the MLS data for any other use, such as re selling it to Zilow or other agents or buyers etc, the MLS board would fine me, drop me and possibly litigate about it. I fulfill my agreement with MLS by using their data in appraisals when I join as an appraiser. Were I to join MLS as a RE agent, I'd have a different agreement with them.