Nice question that illustrates an interesting undocumented feature.
Richard Warr (9/10/2013)
I found some supporting documentation here. Seems a bit of a "hidden gem" though :crazy:
Back in May Microsoft said this was by design and they were going to document in BOL, and in June they said it would take a couple of weeks to make the change. (see this connect entry).
Twelve weeks on it's still not documented in BOL (not even for SQL 2014). I wonder if they've forgotten?
edit: get link tags right