I think it's less disruptive just to nurse the baby, unless he won't do it quietly, than to get up and leave a function. Of course, the really little ones often have diaper disasters right after eating, so it's a judgment call ...
He was fine. Our pew members were a little disturbed, but he wasn't the one to have disasters during feeding. He was just displaced since we had to travel a long while and he had overfed and then barfed at my aunt's home prior to our going to the wedding.
He slept in his car-bed (a very cool thing that folds up to about the size of a lunch box) through the whole very noisy reception.