Y'know, Archie, suppose we narrow the "proof" issue down to swivelling electronic LRL's. That's what the vast majority of the discussion here is about.
I can't prove swivelling LRL's don't swivel. In fact myself and others have pointed out repeatedly that whatever else they do, that they do. Hand-held swivelling "locating apparatus" has a long history that predates electronics and even coat-hangers, it's not like we don't know what the things are. They really do point at stuff. The debate is not whether they do, it's over why they do and why people get the idea that's a useful feature. That debate does not depend on electronics.
Add electronics (even electronics that aren't even bogus, they're literally pretend) to a swiveller which is recognizeable of the dowsing variety, and now it gets called an "LRL", often "molecular frequency discriminator" or some such.
Now we've got fraud. What makes it fraud is that the claims the manufacturer makes about the electronics are fraudulent. If you don't know anything about electronics, then you can imagine electronics to be whatever you want it to be, and the manufacturer knows what you want it to be.
If you do know electronics, then you recognize the thing as fraud.
In most cases, even if you don't know electronics, you can recognize the character of the salespitch and indeed the whole business operation as being indistinguishable from fraud, which ought to make you a bit skeptical!
But when it comes to proof, nothing will suffice for you. Nobody can either make you understand electronics against your will, nor trust what people who are knowledgeable in that subject matter tell you.
And if a business operation that is indistinguishable from fraud no matter where you look doesn't give you cause for a bit of skepticism, then you can actually blow your life savings on the gizmo and even after having it in your hands, you'll be a happy camper. It'll point at stuff as long as you're holding it in your hands, and whether or not the electronics have anything to do with that won't make any difference.
So proof that you're being defrauded cannot avail you. You can always find a way to pretend the proof isn't there since nobody can make you understand it and nobody can make you acknowledge the proof even if you do understand it (since it's not what you want).
The major manufacturers understand all this quite well. The people you regard as "skeptics" are actually in agreement with the manufacturers as to what they're selling. We just happen to not like consumer fraud, even that committed against gullibillies.
So, if it's "proof" you want, stop whining about "skeptics" and go straight to the source -- the manufacturers-- and "read the advertisement". If having done that you do not have your proof, save up your money and buy the thing! If you don't know which make and model to be saving up for, I recommend the Thomas "Gravitator" -- it's worth its weight in gold-- Thomas says so and I say so. And oddly enough, it's not a "molecular frequency discriminator", it is a "gravitator". Thomas says so and I say so. Truth in advertising! don't you just love it?!
--Toto