Retrieving an album from the Offbeat Path room

I knew I'd requested an esoteric album at the main county library, Headquarters, when it had an H+ sticker.  A Beatles album, for instance, would have an H sticker and be out on the floor with the rest of the albums anyone could check out.  The album with Donald Erb's piece, "The Seventh Trumpet," however, was an H+ selection and wasn't in the main area with the other albums.  You could only check it out if you filled out a request form.  When your library only has so much space for a collection that keeps expanding, that system makes sense.  I always wondered who decided what was obscure enough to be kept in a back room for requests only, though.