He's also a royal of England, a nation that was on the direct front line of the Nazi assault. Furthermore, you want the position of a Royal, well welcome to the world of responsability that comes with it.
This has been bugging me all morning. Going in an animal costume made no sense, given the theme of the party. I think perhaps Prince William was dressed as a Mau Mau. I have been trying to find out some of the dress of the Mau Mau, but have been unsuccessful.
From my memories of the Mau Mau, they sometimes wore lion heads to intimidate the colonial British. The Mau Mau uprising occurred when I was a child, so I may have a faulty memory. I think this is important to look at, as the Mau Mau were terrorists.