This is an example of Conservation of Detail, which is just another way to say that the contrapositive of your statement is true: if you don't need to take something in a game, then the designer won't have bothered to make it take-able (or even to include it.)

I always assume that there's all sorts of stuff lying around in an RPG house that you can't see, because your viewpoint character doesn't bother to take notice of it. It might just be because it's irrelevant, but it might also be for ethical reasons: your viewpoint character only "reports" things to you that his system of belief allows him to act upon.