Social.localUser will Automatically call GameCenter Login Screen - How do I stop that?

 Social.localUser.Authenticate(ProcessAuthentication);

If I am not logged into GameCenter on my iOS device, this code triggers the login screen.

I don't want that, how do I stop that from occurring?

The problem is, this login screen changes my Game Orientation from Landscape to whatever the device orientation is, effectively over riding my settings. Even if I put;

     void Update()
     {
         Screen.orientation = ScreenOrientation.LandscapeLeft;
     }

In my code.

I either need to stop the login from occurring or control it's Orientation.

Anyone else have this issue?