Nothing terrifies parents more than the thought of calamity befalling their children. Kids are our hopes, our dreams, our future. More than that, helpless and trusting things that they are, they look to their mommies and daddies to protect them from all the evil in the world. Parents' greatest fear has to be that someday they'll drop their guard just long enough to leave their youngsters vulnerable to the wrong people.
Parents worry about madmen on the loose and about the "responsible" people they leave their kids with for an hour or two. No parents can watch over their children 24 hours a day, hence the underlying anxiety in the following legends.