The Aumann results require that the two of your are honest, truth-seeking Bayesian wannabes, to first approximation, and that you see each other that way.

You also have to have the time, motivation and energy to share your knowledge. If some brat comes up to you and tells you that he's a card-carrying Bayesian initiate - and that p(rise(tomorrow,sun)) < 0.0000000001 - and challenges you to prove him wrong - you would probably just think he had acquired an odd prior somehow - and ignore him.