The idea that a good boy should return the things borrowed by others is right. No matter how imperfect the management of this library is, no matter how many respondents say that it doesn't matter to explain the situation directly, you can compensate for the lost books according to the price. In addition to the law enforcement agencies stipulated by the state, other libraries have no right to impose fines, let alone detain you. However, I really give you some personal advice. Besides reading books, you should do more social practice. Although others laugh at you for being wrong, your understanding of society is indeed a bit excessive.