The low fidelity non-feature in Lucid Spec

I'm a big fan of the book Paper Prototyping by Carolyn Snyder. The book discusses how to create low fidelity (crude black and white) paper prototypes and then use the prototypes to get useful user feedback to better understand requirements and general usability. Joel of Joel On Software has said similar things about creating low fidelity functional specifications to flesh out design and usability issues. The basic idea is that low fidelity prototypes help users focus on how something is supposed to work rather than on whether something is pretty. You may have been in design meetings where users become focused on the color of a widget instead of whether that widget provides the necessary functionality. I know I have.

Therefore, I assumed that many users of Lucid Spec would request a low fidelity option to automatically morph all screens into a simple black and white style. I assumed wrong. In fact, not one user has requested this feature. I'm not really sure why this is. Are low fidelity prototypes something that you should do, but don't? Do people that create low fidelity prototypes only use paper? It remains a mystery to me.