A long enough, massive enough stick could theoretically be a gravimeter. You'd just have to be so impossibly perceptive (or use an interferometer) that you'd notice the difference in gravity each half of the stick experiences.

No question dowsing is pseudoscience. But it's interesting that the dowsing concept of hanging weights off a stick is quite similar to the first scientific gravimeter, which used a pendulum in the 1670s.

Also Clarke's first and second laws in action: "LaCoste's most famous invention is the ship, and aircraft-mounted gravimeter. …this invention was considered impossible until LaCoste demonstrated it." Clarke's third law is asking the black brick in your hand "Siri, what's the local gravity here?"

No it is not. But can a human+stick system act like one? I'm open to the explanation how it would break the "laws of physics".