Didn't seem like it was too hidden to start with, not everyone believes in them but most people at least know the stories. That was always one thing that amused me about Japan, so many people believe or semi-believe in spirits compared to the rest of the world where you are expected to outgrow that. I can only imagine (in story anyway) that that belief must've helped the spirits in the long run.
EDIT: And I found this translation of the Omake in the first volume:
disguise time!