Other's mistake could be your unlucky day

Sometimes one person's laziness or mistake could be another person's trouble. Went to library to borrow a DVD. Somehow the DVD was cracked. So the librarian missed it. Carelessness or mistake? Since the box was sealed it would be the librarian's duty to ensure the disc is working. Well, when I took it, I made the mistake of not informing the library of the crack. So when I return it became my problem when they claimed that I broke it. They need a better system to ensure the correct person gets the penalty of the damage. Maybe it was me being unlucky.