Despite his wedding possibly being watched by a quarter of the world's population, Prince William does not want to put all his eggs in one basket. Specifically he has announced he will not wear a wedding band. This way when he heads off to the deepest darkest jungles of Africa and people with no televisions he can pretend he is not married. Yes, that ring tan line would have given him away. Maybe this is his way of hanging on to the single life. Maybe Kate Middleton does not love him enough to put a ring on it. Maybe he thinks there are four or five people who will think he is Joe Blow from Derby and would be more likely to sleep with him if he is not wearing a ring. Maybe he is saving himself for his true love Camila.
So, the vows will go something like this:
William: With this ring, I thee wed.
Kate: With this imaginary circle I am making with my fingers, I thee wed.
Should make for fabulous television.