Steve Jobs and the empty space on the iPhone 4S Keynote

This year's iPhone keynote was well known, not as before in the Yerba Buena Center, but instead of directly on the Apple campus in Cupertino. As you can imagine very probably at an Apple event, all seats are reserved, even this time all the seats were fully booked, but to the last.
In the front row was a chair that is still free, placed directly in front of the stage. At the head of the chair is