  Consider a persuasion game where both the sender and receiver are ambiguity
averse with maxmin expected utility (MEU) preferences and the sender can choose
to design an ambiguous information structure. This paper studies the game with
an ex-ante formulation: The sender first commits to a (possibly ambiguous)
information structure and then the receiver best responds by choosing an
ex-ante message-contingent action plan. Under this formulation, I show it is
never strictly beneficial for the sender to use an ambiguous information
structure as opposed to a standard (unambiguous) information structure. This
result is shown to be robust to the receiver having non-MEU Uncertainty Averse
preferences but not to the sender having non-MEU preferences.
