Copyright issues and realism

So, I have this question that struck me tonight and I’m hoping my army of readers (cough) can help me out with a resolution to it.

I’m faced with a nagging question – its relevance is no concern of yours. 🙂 But the important question is: do copyright and/or trademark issues prevent realism in stories and movies?

We all know that it’s a rare, rare thing to find realism in fiction when it comes to computers. Is there a known copyright or trademark fact that prevents this realism?