I don't think there would be that many taking the Metro. IIRC, on Monday night, they said there were a few dozen who missed the trains. what we are talking about is making it so no one would leave early by having late trains available. Metro probably has a good idea of game / nongame usage of Navy Yard just how many people attend. Metro only gets an increment from the people who otherwise would drive or not attend if there were no post game guarantee.