I see in Design Pattern Framework, errors that are returned from the service layer via the response object are swallowed in the repository object. As an example, try turning off [Authorize] in the AdminController. The web service fails to authenticate the user and the list of customers (calling Customers method) is null.
I would have thought the best (if not only) place to handle the display of these errors is to use the ResultSummary method in the view. The "result" to be added could be the error message returned from the response object. However, the controller needs to have access to at least this string, and the response is not passed back as far as the controller. How have other members handled this?