"Er, well, they're noted for their stylishness," Rincewind says. "They're always well-dressed. And they have a very good school." He frowns, not really sure what else to say about them. Perish (literally) forbid that anything might get back to them. "But," Rincewind's brow wrinkles in puzzlement, "if I do that, they won't be lost."
"They can hurt plenty without being broken." Rincewind is quite certain he's not telling Xellos anything he doesn't already know.
"Certainly not!" Rincewind is aghast. "Not unless you wanted to spend the rest of your life with your head the wrong way round! The Librarian is very strict about things like that. And there's enough trouble in the library on it's own without anyone bringing in more. I was an assistant librarian," he tells Xellos with some pride*.