Congrats on your 5th!
DH & I went to Disney last year for our 15th (and plan to go this year for our 16th). We didn't have any expectations of anything (except of course of having a great time). We didn't even know about the buttons until a photopass CM told us where to get them. It was fun because everyone (from CM to other guests) who saw them congratulated us.
We were staying at a cabin at Ft. Wilderness and when we arrived all the CMs got so excited (a bit strange we thought) because there was a "special envelope" for us. In the envelope was a certificate from the CM that I booked our trip with. THe certificate congratulated us on our anniversary. So then all the CMs made a big deal about it. It really made us feel special!
Also, at Trail's End when we were having dinner one night, our waitress noticed our buttons and we told her we were celebrating our 15th and she was very sweet and nonchalent. She left to go to the kitchen and when she returned she presented us with another certificate (where the entire staff had signed) and a really yummy strawberry shortcake (which was just the perfect size for me & DH). It was soooo good!
Just my 2 cents!