I don't know how well this would work for a formal affair, but they could design their own as an icebreaker activity. My wife has had to do this at a baby shower before. I think they might have even had to get to know one person and design the tag for that person. It could get the whole thing started in a more friendly manner.

Of course, there will always be a couple stodgy party poopers who won't want to participate. Those are the ones who will complain anyway. Some people choose to have a lousy time no matter what.