I'd tell the coach, "We'll never know."
I will have no opinion of any calls that my partners make in their primary areas, and I would simply tell that to any coach who asked along with advising him that he needs to ask my partner what he saw on the play. However, I will definitely have an opinion on a play which takes place in my primary area, and if I have a whistle on the play and my partner doesn't let me make the call he is certainly going to hear that opinion.
