I see this as a design flaw in Evernote (when a notebook is selected its tags are cluttered with other notebooks tags). In your case, what's the benefit of separating your notes into different notebooks at all? I (mainly) would separate notes into different notebooks for precisely the functionality that Evernote does NOT provide. Therefore not worth it to me. e.g. I'd put my "Financial" notes into a "Financial" notebook just so I could see ONLY the relevant tags (in GTD parlance - tags = project manila files). I don't want to see my Travel files (tags) when I'm in my Financial notebook. Else it's not a "Financial" notebook is it ! I do want THAT functionality as a matter of priority!