Well I can tell you that my ghost-hunter sister took some photos in there (I know, we weren't supposed to but there was hardly anyone on the attraction) and when we had them developed there were all white spots and streaks of light. This is believed to be ghost energy according to those who study this sort of thing. She has gotten similar spots in some old cemetaries here in Connecticut that are famous for being haunted. I don't know what the spots were, ghost energy or not but every time I enter that room now, I get creeped out. But then its just like our "ghost host" tells us, the haunted mansion has "wall to wall creeps."
If you're a believer, one of the ways a place can become haunted is by the energy that is created by the people there. Maybe Leota's spiel has attracted some supernatural energy over the years. If you believe that sort of thing....I am not entirely convinced but I try to keep an open mind.
P.S. I am talking about the HM in WDW.