One of my short stories takes place in a not-to-distant future, where there is absolutely no privacy. In one chapter a child goes to a bathroom in an old building, and he sees that there is not only a door, but there is a contraption on it. A lock! The child runs out of the bathroom in fright. The audience learns only a little later that the child is frightened about what human-eating animals might stalk prey in that area, that anybody would ever think to lock themselves in there.