Selling a haunted house without informing the buyer???? law?

From a legal stand point , in most cases the buyer is just stuck & will have no legal stand as they would have to prove the previous owner knew the house was haunted. Which in most cases would be impossible , as that's why they were selling it in the first place. In the case you cited the house had been publicly announced to be haunted & published as so , that was all the proof the new buyer needed to get his refund.