Reportedly, illegal porn images are hidden somehow on sites that are meant to contain legally allowed porn, and this puts innocent visitors in danger of being imprisoned for something they did unintentionally.

Any law that makes it a crime to have a copy of some published works is a terribly dangerous injustice. These laws must be eliminated.

Does anyone know more about the technical practice that the article describes? Merely using a shortened URL does not "hide" the page it refers to.