Good question, Nils.  According to what I have learned from attorneys I have worked with, there's a theory in law known as the doctrine of practical obscurity, which essentially states that although a piece of information may be publicly available, the fact that no one with more than a casual interest would go to the trouble of looking it up makes it, for all practical purposes, obscure. 

So while the individual pieces of information we examiners collect, standing by themselves, are considered "public" in nature, they become "non-public" once assembled into a narrative report or an abstract of information relating to a specific person or parcel of real estate.  Back in 2008, I wrote a blog post on this very subject, to which I am linking for anyone who cares to review it. 

Regards,
Scott Perry