Here is a link to an interesting article about the problem of attending a wedding when you are gluten intolerant.
I just returned from the wedding of one of my oldest and dearest friends. Food was definitely a concern for me and Mom, as the wedding was in a small town, without so much as a McDonalds nearby. I talked to my friend before hand, and he was willing to talk to the caterer for us. (God bless you, Jonathan!) We were exceptionally lucky. They were serving barbeque, which is frequently gluten free, and the caterer confirmed that there were no gluten ingredients in any of the meats, sauce, or side dishes. Yippee! It was simply a matter of skipping the rolls and the cake -- easy as (gluten-free) pie.
Just for review, here are the items I asked Jonathan to specifically ask about:
wheat, flour, thickeners, roux, chicken broth, beer, and soy sauce. Those are the key words I always use, since not everyone understands "gluten" or even "wheat."