Board Thread:Administrator's Noticeboard/@comment-1250011-20131107193327/@comment-7697305-20140702004728

I don't believe it would; doing it the way I described is a shorthand way of saying that all of the pages in the category fit the definition of "Rare Items" (which they do – each banner drops at a rate of 0.5%, right?) rather than that banners in general are rare. Not adding every individual page to the category also has the advantage of not cluttering up the category as much.