First off, that scared the crap out of me.
What do ghosts think they're trying to prove? There was a special on TV about a house in France built on a World War I battleground that reported paranormal activity.
Ghost of a soldier: "How dare you build your home where my brothers lived and died in bloody, mud soaked trenches! How could you!? I'm so mad!! I'll make you sorry!!"
*moves a teacup two inches*