I have so many images where a person or people enhanced the sense of scale and meaning of the actual location. I have many shots of Grand Canyon area like this. Without people, magnitude of scale is unimaginable and without people, the fact that it is a popular tourist location isn't apparent. (I have one that people are basically crawling all over the place) I'd post a sample but it was digitally captured, so I wont.

I also have shots where I waited (for a long time) for people to go out of the view.

I think, as long as your views and pre-visualization permits them and they aren't doing anything disturbing (like picking their noses), people can enhance landscape images. So as always, my answer is "it depends!"