We don't straighten out piles of clothes, papers, etc. I tell my client that in order for us to get to all the areas that need to be cleaned, they need to give us access or make way for us to clean.
I have it in writing, and I also tell them orally.
If there are a few CDs, DVDs, books, etc. - the best I will do is stack them up to give me room to clean if they're spread out over a surface; but nothing more.