I just discovered something interesting. A roSpringBoardScreen with no buttons will not generate any events whatsoever. I realize it would probably be an extremely rare thing to want to do, but it still seems like the incorrect behavior and in the interest of saving other developers some frustration, I figured I would share.
In the process of mocking up a channel, I built a roSpringboardScreen with no buttons. After navigating into that screen, pressing the up button on the remote did not close the screen. Likewise, the left and right buttons on the remote did not generate their expected events. Adding a button to the screen fixed the issue.