Erik Has Trouble Dealing With the World (I)

Why is it that 2 of the 3 libraries that I frequent on campus continue to ask me if I'm checking out the books I bring to them? What the fuck else am I doing with them? Do people answer this question in a way other than "yes"? I mean, there are drop boxes for checking back in. I suppose you could bring them to the counter to check them back in, but is it so common that you actually have to ask if I'm checking the books out?