Do the old mailbox trick.
place an Iron Cross (steel, aluminum etc) and ‘camo’ it with wood.
If ‘they’ take clubs to it there hands will suffer.
If ‘they’ burn it, it will (defiantly) still be there.
Put a web cam on it, and- if the establishment won’t recognize ‘private property’, a little deck plate justice never really hurt anyone— relocate some critters, including the slithering kind.
Make the little SOB’s work for their pleasure...
The terrain would preclude the webcam idea, but a steel cross set deep in concrete would help. Go to the click through the link to the Daily Press and expand the picture. You can see how rough the terrain is. My son and I drive Stoddard Wells Road to get to Costco. The rocky outcroppings are really beautiful, but nobody notices because they are mostly on the freeway that runs along side it. Frankly, I never noticed that cross.