If a user is not connected to a player they can still navigate through menus and select items to play, however, nothing happens if a player is not selected.    

A simple popup screen alerting them that no player is connected would help dramatically.  Another method would be to highlight the player drop down menu illustrating that they need to choose a player to begin...Another method would be to render SC inactivate until a player is chosen.

In addition, moving the text "choose a player," up a level to appear at all times when a player is not selected would be helpful to new users.