let me give you an example.
a year ago, when i was working on a term paper, i needed a book on business law and found a copy in the law school library. however, the librarian turned down my request with a cold shoulder, saying, “you can't borrow this book, you are not a student here.” in the end, i had to spend 200 yuan buying a copy; meanwhile, the copy in law school was gathering dust on the shelf.