Just because they are in a vault.* The way to discourage some patrons - let's say me - would be to park the books in a prominent location with a big sign saying Read Me.
I'm not exactly quibbling with the ALA. On the one hand, they are dreadfully liberal, seemingly confusing censorship issues with the public's obligation to buy books for the public with public money. On the other...they did allow me to visit the exhibit hall at their annual conference and walk away with a ton of fabulous literary swag. Which hand would you bite?
Do all libraries have vaults? I know the librarian at my college library had a shelf above his desk with the school's limited erotica holdings. Our local library? [Emily, please do fill us in!] (I don't spend much time at the local library - since they confiscated our 'outlaw' cards. The holdings just don't appeal to my tastes and ILL requests take too long, so I can't bring myself to shell out $80 for a card.)
I would take issue with the term vault-like. Isn't a room with metal doors with a heavy duty combination lock called a vault?