I use WP as a CMS. Current project has a menu with sub-menus. The client wants some of the top-level links to just be "guides", ie. they won't represent pages, but their sub-menus ARE linked to pages.
So top level could be something like:
Home | About | Products | Contact
The "Products" item will have a couple of sub-menus items linked to live pages, but the Products item itself isn't linked to a page. Make sense?