I've participated in similar activities worldwide. It is something called "geocaching". Usually the gifts are not worth much, but you get clues where the cache is hidden and you go find it. There's even an app for that!
https://www.geocaching.com
Usually the caches are off the beaten path, and are really just for exploring. They are not attractive enough to lure lots of people to them. Try the app. There's probably a cache near your present location.
What I don't like about this particular one is that it is sending people through private property onto a possibly risky part of the property that could result in the hotel getting sued for something. How would you like it if you had a stream of non-guests walking in front of the ocean-front room you had to pay a lot of money for to go look for this? It is attractive enough at $100 minimum that I'm sure will get people trying to find it. It is almost as troublesome as the various "Revealed" books that have resulted in many beautiful places being permanently closed because they were overwhelmed by the attention they garnered through the books.