Does it really work? I don't know, but I have heard some stories about dogs detecting an MFD signal line, and one that actually digs up the target the second the transmitter is turned on--it was cash.
This brings up map dowsing. I assume the dog would have an easier time with less distractions compared to outdoor work. And the one guy told me he had the best luck when the dog wanted to go out for a walk. The dog would sit or lie down on the MFD signal line--one time sat there for nearly twenty minutes until the owner "finally took his word for it " and the dog was right on the line. The reward was to take a walk. (Guess it depends on how bad it had to "go". LOL The owner said he was map dowsing and the dog just perked up like it had seen something.
Can't remember but I think it was Bill Cox who talks about having a connection with dog through the solarplexus.
So I think this is totally plausible as they would say on Mythbusters TV series.