Quote - Ok here is my question, I understand all the references of copyright infringement with images, intellectual property  etc and would imagine that texture files are easier to claim and protect, but how does that apply to shaders and nodes  that use only the mathematics in the material room?, one single adjusted setting and it is no longer the same beast.

A shader basically performs a mathematical function. Mathematical functions represent ideas and are therefore not copyrightable, even if no settings are adjusted (at least not with US copyright law). A different matter would be the specific representation, i.e. the poser nodes, the fact that the diffuse node is on top of the specular node etc. I would guess that there is too few original work involved, so that even those are not copyrightable, but i am not sure. That would mean that you could basically copy a shader without bad conscience (might not be the politest way, but you know how artists are :-)

Quote - It must be virtually impossible for any creator that uses shader nodes to prevent their shaders being "borrowed", resused etc etc.

Yes, this is probably the most widespread way to use shaders. I doubt that all those pretty marketplace shaders were constructed by trial and error, or by a deep understanding what mathematical functions the various nodes actually perform.

Quote - I'm asking this question because I'm in the middle of a project and am wondering how to protect my work once it is completed, and therefore whether it is better to use texture maps or shader material settings alone.

Of course, easiest would be to not post them on the internet :-)