We celebrated two birthdays at the POFQ last month, and they did not to anything there. I had them make a note on the reservation, and I mentioned it at check in. I also mentioned my cousins 6th birthday the night before when I went to the front desk to ask for scotch tape to put a banner that I had made at home together.
We did get a couple of free desserts in restaurants, and a nice cast member in the United Kingdom gave each of the birthday people a lanyard pin one night.
I wouldn't expect anything, that way if you don't get anything, you won't be disappointed. If you do get something, you'll be thrilled.
Karen