I suppose that it doesn't HURT to ask...but if you care about what other people think...to me...it's kindof like being a guest in someone's home. You can find a way to work it into the conversation, and maybe something nice will happen. If it does, great...if it doesn't, great. You're getting a husband/wife! That's your prize, right? And they're there with you at the Happiest Place on Earth, right??
But when a CM hears "Do you all do anything special for 'XYZ' ??" it is SUCH a big turnoff. They may keep a smile on their face, and you may get free dessert, but people will be rolling their eyes at you in their minds the whole time. This may seem a little harsh, but it is completely true. Part of the reason I joined this forum was to help educate people about Disney and help them be able to find their own Magic without it always having to be handed to them on a silver platter. As a front-line CM, it is often up to me (I use 'me' generically) as to whether or not I want to take the extra steps necessary to make some Magic. I mean, face it, I could give you the most sincere smile when you asked me if we do anything special for whatever and say "That is so great! Congratulations!"...maybe engage you with a little small talk and go about my business. In Disney's eyes, I have done my job and then some just by doing that (backstage we call it a Take 5...we took a few seconds to stop what we were doing, and make you "feel" special) and am not obligated to do another thing.
But that's not what most people mean. When they say "do you do something special?", they really mean "what are you guys going to give me?" In that moment, again, it is completely up to me. I could go the extra mile...go talk to my leader and "see what we can do"...but practically speaking...can I do that the 20-30 times a day (I'm not exaggerating) I get asked that question? No. So I end up with this judgement of who "deserves" it.
It might seem all unmagical and judgemental and power-trippy to you, and it isn't meant to be that way, but it is true. That decision is ours to make, and most of the time it has to be made...just out of practicality's sake. So...and I can only speak for myself...but...it makes sense that many other CMs might feel this way...it's almost an unspoken policy IMHO...who deserves it? The person that doesn't ask. The person who made eye contact with me while they were in my line, struck up a conversation, mentioned that they were here celebrating something...(didn't throw in a gratuitous "so do we get our meal free/to go to the front of the line/etc...[laughs] of COURSE we're just KIDDING!!" when they aren't)...and went on their way. That makes my day interesting, and makes me want to make it MORE interesting by surprising you as you're leaving the attraction, or acting like I'm not going to do anything and then coming out with a dessert at the end of the meal...something like that. So again...this may all seem mean-spirited...but I'm really just trying to help you get what you want. I'm not a big Bible quoter, but..."Blessed are the meek!" Try it...it works!