More from the Unhealthy Curiosity Department

Isabel and I were watching the recent new episode of Ghost Hunters where they claim to make contact with the ghost of a woman at the Buffalo train station using their K2 meter.
I don't really know what K2 meters are supposed to detect, but the Ghost Hunters claim that it will light up when a spirit tries to "touch" it. In the episode, it appears to light up on command when they start asking questions to "anyone in the room." They have a relatively lengthy conversation with the spirit, but they can only ask it yes or no questions given the way the machine works.
The first, technological problem, is that I don't see how they know the machine isn't just picking up whatever it is meant to pick up. That is, how do they know there isn't interference.
Second, even if the Ghost Hunters are sincere in their efforts, it seems like it would be easy enough for the Sci fi Channel cameraman to have some device that he activates so the Ghost Hunters think they are getting a read.
The final problem I want to point out, and its what makes me the most skeptical about the show, is that if they really thought that they had made such intimate contact, why would they ever leave the scene? And why wouldn't they ask better questions? And why wouldn't they create some kind of giant K2 meter keyboard that would let the ghosts type out their answers?