You may want to mention that if they aren't paying for the reception that they really don't have a say. (Do so in the kindliest way you can, of course.)
It was an issue at my daughters wedding. Someone forgot to tell the DJ and he stopped the music to offer a toast and was floored when he heard that we don't do toasts. That's why Witnesses are better know for what the DON'T do than for what the Do.