Most we have stayed at didn't have any and we bought a few to put up. Last Christmas the TH we stayed in at Windsor Hills had a tree and decorations which the owners said we were more than welcome to use.
We bought a fibre optic tree one year and left it packaged in the box with a note saying they could keep it if wanted. I certainly wouldn't cause any damage by sticking decorations on to the walls etc.
We have booked for December, when I was making enquires it was a mixed bag of some villa owners providing decorations and some not. We ended up booking a villa with no Xmas decorations provided. We are there from the 9th to the 24th, I think I might just buy a small fibre optic tree or similar from Walmart for the living room....