It's a public park and, in particular, the National Mall is oft called 'The Nation's Front Yard' in reference to its status as one of our earliest public parks.
That said, skating on the Reflecting Pool while it is frozen over to a safe thickness of ice is absolutely conducive with the purpose for which the park was designed. I do believe that George Washington, Thomas Jefferson, and Pierre L'Enfant would have been very, very pleased!
![Drink up [B-o]](./images/smilies/drinkup.gif)