It's about the tools used to create illustations. That is why "software used information" is not simply ethical it is crucial.

The question: Was it modeled and textured in Zbrush (which is the heart of the art) or Carrara? Or was it only rendered in Carrara? Why should there even be the question? The information should be provided. PERIOD

I think this type of question is valid. For a commercial company selling software for illustration it is a simple question of ethics and honesty. It is better to share correct information than pose and dance as something you are not.