During the ceremony everyone in the crowd was photographed. This website shows the main picture of the event but if you zoom in or double click an area then the focus changes and the face can be seen in detail.
The picture was taken with a robotic 1474 megapixel camera (295 times the standard 5 megapixel camera). Everyone attending could be identified after the event – presumably just in case you’d left something behind for example. (and yes … someone IS doing some personal grooming on their nose)