We just got back from our honeymoon and we wore the ears the whole time (actually, I wore a white hat with the veil beanie on top so I could have a brim). We got tons and tons of "Congratulations!!!", which felt like special treatment. We also got bumped up to a king bed (though we also checked in very early in the day). We got free ice cream from one of the stands, a free mickey/minnie heart pin from one of the cast members just walking around Epcot, free good-any-time passes for Test Track, lots of love and affection at Cinderella's Breakfast (plus Royal Table champagne glasses as a gift), and mostly it was just so fun to have more than half of the cast members smile, wave, and say congrats. Plus all of the other people who stopped and said, "We honeymooned here 4/10/20 years ago! Have a wonderful time!" Oh, and we also got a signed picture of Minnie and Mickey slid under our door at AKL saying congrats and all that. 
As others mentioned, it's not something you can count on because we didn't get free stuff everywhere we went, but even without gifts, I thought the attention made our week extra special.

As others mentioned, it's not something you can count on because we didn't get free stuff everywhere we went, but even without gifts, I thought the attention made our week extra special.