*Long post...sorry.*
Now before you shut me down, please hear me out... I've read mixed reviews about sending surveys with your Save The Dates—some people think it's rude, while others think it's genius.
The vision for our wedding is to be very people-centered. I want it to be more of a big family/friends get-together than an all-about-us day (shocking, I know). With that in mind, the survey I would like to send out is more about determining things about our Save The Date recipients that will help us make it a comfortable day for them as well (especially since many of them will be coming from out of town)—I don't remember what all of the (whopping 4 or 5) questions were, but two of them had to do with food allergies, and what aspect/tradition of a wedding means the most to each recipient.
There would be a question about the likelihood of their attendance as well (*gasps!* the horror! )—with multiple-choice levels of probability ranging from "Heavens yes!" to "It's a 50/50" to "Sorry, we're so excited for you, but we can't"—but it would be worded in a way that conveys no obligation, that their response definitely doesn't lock them into coming/not coming. It's just to get a general idea. Plus, my contact information will be on there. I want to make it clear that I am open and reachable should they have any concerns or questions.
Thanks for reading the clueless ramblings of a new, green bride. Any and all insights from wiser, experienced ladies would be most useful!