The spirit doesn't give any luck but it's more of exact instructions. Most people ask for some type of figure and when they get that figure, they use part of the funds to pay for the festival. Throughout the year, people always ask for things at the shrine and I suppose that's how they're chosen. It's not always people who need money. Some people want the impossible and for that impossibility, once they get it, they have to treat the town with the festival in return. The 3 ancestral spirits just want to see the family (town) gathered and want to see their favorite forms of art.
And the waterfall is a secret because it's unmapped despite having that nice sign. If you google Ton Pliw Waterfall, it doesn't come up but I assure you, that it's there. Only the locals really know about it and all the school camps that visit Khao Chong never get to see it. I just got lucky, I saw those 2 monks, LOL. Thanks for coming by and hope you have a marvelous week!
"We appreciate you joining us on our travels..."
Wishing you the best, @adsactly & @stewsak