So glad I'm not the only one interested in looking at a map to help understand the story. The runway numbers did indeed change, back in 1999: https://en.wikipedia.org/wiki/Ronald_Reagan_Washington_Natio...

Agreed that the pilot definitely made a huge, and not really reasonable mistake. Even though it was pre-9/11, I'd expect a pilot who was going to fly in/around DC to know there's going to be restricted airspace and to take the time to understand it.

(if link doesn't work, go to the Wikipedia article for Ronald Reagan Washington National Airport, and look at the bullets under "Expansion and restrictions")