Well you never really know, do you. Maybe Halloween has something special about it, even if it is just the feeling everyone gets, thus making them a bit more in-tune with seeing here. Maybe she always walked around the graveyard at Halloween when she was alive and this is here doing it after she's dead. Or maybe someone saw way too many Scooby Doo episodes and has a projector hidden in a tree. And THAT sounds like a Sci-Fi Original movie to me if ever there was one.
Gabriel