Non-speciaisation librarians who work in uni libraries....
...and refuse to call up the specialised librarians who might actually know the answer to your question, preferring to give their own opinion.

Favourite example so far was when I tried to get an orchestral set of Faure's "Requiem" out of the library. The librarian returned with a timpani part, a score, and three brass parts. She then argued with me for nearly five minutes that, "That's what's on the computer, therefore it must be a full set... I'm sure it's perfectly playable."
(Sivvus trolley collision in the fruit aisle led to a jam, Thu 27 May 2010, 12:38, 4 replies)

Jeesus.
My music dept was blessed with a very good library.

If you're anywhere near London, try Senate House and Westminster Library, both have excellent music sections.
(The Empress it seems you CAN polish a turd!, Thu 27 May 2010, 13:11, closed)

Lancaster, unfortunately
Apparently Leeds is pretty good.
(Sivvus trolley collision in the fruit aisle led to a jam, Thu 27 May 2010, 17:31, closed)

Haha, you don't go to MMU do you? Worst library ever. Sometimes I think the MM stands for Mickey Mouse... Public librarians are worse though, it really wouldn't hurt for them to smile once in a while and be slightly polite.
(TruckfulsOfWoo, Thu 27 May 2010, 15:07, closed)

It certainly is known as the Mickey Mouse University
I went there for two different degrees, 20 years apart, and the exact same books were on the shelves both times. Tattier but recognisable.
(Juan Quar is clinging to her front teeth on, Thu 27 May 2010, 15:50, closed)