Here is a "joke" news story about an elderly woman who was repeatedly terrified by noises and blue flashing lights in her home at 3.13am. The first person she asked for help told her she had a ghost named Jack. The second person, a church minister, told her she had two ghosts, one of them a suicide, and recommended she place crucifixes in all the haunted spots. When the elderly woman took matters into her own hands, did a little of her own investigating, she found the answer!http://www.stuff.co.nz/oddstuff/4907864/Irene-terrified-as-ghost-comes-a-calling
The point is that it is grossly irresponsible to tell people they have a ghost in their house. Neither of these people who were asked to help even bothered to check properly, or they should have found the answer themselves. What if the woman had instead decided she couldn't cope and moved out, or some other worse outcome?