I’m not laughing, I once saw a man with two bent pieces of wire locate an underground cable after a man with an electronic metal detector failed. Maybe it was luck but I saw him do it. Sometimes luck is better than knowledge.
As the guy with the fancy metal detectors (and more) - I have seen that too! (There is physics behind the bent wires).
I have also seen where a guy held a piece of gold on a string over a map to find out where the buried treasure was three states away. Not sure of the physics behind that!