DU librarians! How do "restricted book lists" work?

[kay1864]

(I posted this in a "fundie wants to ban Harry Potter books" thread, but never got an answer. Do any of you know?)

How are the books restricted--are they in a special "behind the counter" section of the school library, or are the books just coded in the computer as restricted? (note that the second approach doesn't prevent the child from reading the books, but only prevents him/her from checking them out of the library)

Does the school send a list of restricted books to parents each year?

I'm asking because an Atlanta fundie is trying to ban the Harry Potter books in her county (I've posted two threads in GD on the topic). She's almost certain to fail failed last Thursday!, but I got to wondering how these restricted book lists work.