Considering the time, resources and effort required to create a good movie or book, which when released to the public is a means of income for the creator, any person who takes certain avoidable steps to hinder the successful transfer of the created work from the artist to the recipient should be held responsible for damages.
Persons who through carelessness or avarice reveal plot points that would otherwise have been a surprise (giving away spoilers) should be legally required to accept recompense for and public acknowledgement of this behavior. Anyone commiting this against another person without warning them or securing their consent should be held responsible and required to wear a sign warning civilized people away.