Confluence 6.1.2
In our space we cross mention (excerpt/include) a lot. This so we can write stuff once, and mention it at multiple location, Because of the dynamic work we do, things can shift. So it happens that an include references a non-existing page.
Secondly, due to the dynamics, pages are sometimes moved to a second space where most users dont have access to.
We only find out if one of the users stumbles upon it and actuallt mentions it. I would like to be notified sooner, unfortunatly these don't show up on the undefined pages.