Yeah No...it's not the rods, or wands, or whatever that they hold in their hands - it is the person themselves who pick up the hint that what they're after is down there.
They could have anything in their hands and it would react if they walked over it, I reckon.
We all know of someone who's called a 'tinarse', or known as 'tinny', who gets the most finds no matter where or what they're looking for - we call 'em lucky, don't we - when we all know that luck is when opportunity and preparation meet, and the majority of the time there is no preparation involved, instead, they'll say something like 'this looks good - let's have a try', and sure as eggs are eggs, Mr Tinarse cracks it. Everytime.
Funny eh...