One of the major players in debunking the hoaxing of Ghost Hunters and other paranormal shows is internet. A simple search of youtube or hulu will give you plenty of examples of the shenanigans played by various paranormal investigative groups on tv.
Hulu has Jason of “Ghost Hunters” reaching up and knocking on a beam and reacting to the strange ghostly knocking noise. He and Grant should get an acting award for this show.
No wonder the name of the group is called “taps.”