The envelope is already in the mail, carrying either good or bad news, and yet somehow the very actof wearing that sweatshirt will cause the news to be bad.
If both parties to the relationship are utility maximizers, there is good reason to believe that the agent will not always act in the best interests of the principal.
In one actof traditional diplomacy, trying to appease the host government, the U.S. Embassy undermined the goodwill earned by the nontraditional diplomacy of Jon Stewart.