http://www.luoamerican.com/baldilocks/2009/03/vengeance-is-his.html

Mystery solved. It seems that the president is seeking to humiliate the progeny of those who humiliated his ancestors. Revenge isn’t that complicated a motive. However, a question remains. Is this any way for a President of the United States to behave? Read also about the gifts which the Obamas gave to the Browns during the latter's visit, especially this one: a collection of 25 classic American films on DVD. Not exactly special. And even more curiously: Brits can't play American DVDs.