The sequel throws us another curve ball. Her brother-in-law WAS the biological father, and the child was given to him and his wife because unwed mothers didn't get a say in such matters.
Big Lipped Alligator Moment: In the movie, and of the non-comedic variety. While Arthur is busy waiting for the Woman in Black to acknowledge the discovery of Nathaniel's body, Mr. Daily has a vision of his son Nicholas which leads him to a tea room, where he's suddenly trapped by the ghost children and sees a ghost child make a creepy face at him outside the window. Then the main plot resolves itself upstairs and the door unlocks itself, letting Mr. Daily go free. But since he was already waiting downstairs with nothing to do.
Cliché Storm: It doesn't stop the story from being very scary though. The play in particular doesn't suffer from any of the cliches as it presents them on stage: horror plays are much rarer than horror films, so the devices seem fresher.
What Do You Mean, It's Not for Kids?: A number of parents in the UK apparently took young children to see the film because it starred Daniel Radcliffe and they thought that a film rated 12A ("recommended for over-twelves but parents can bring younger children in if they want") wouldn't be that scary. After the resulting protests, the BBFC actively changed its rules on horror films to take more account of overall atmosphere and grimness of plot, rather than being chiefly influenced by the level of graphic violence and gore.