It was April, 2001, and the Smithsonian Institution held a Star Wars exhibit in one of their museums on the Mall, that stretch of land between the Capitol Building and the Lincoln Center. See the map, copied from the Smithsonian site. To help promote the exhibit, there were costumed characters outside the museum, including Storm Troopers brandishing (fake) weapons. They were stopping traffic, questioning drivers and waving them on. I wonder if they would be allowed to walk around with weapons, fake or not, in our post-9/11 world. Probably not, and that's just a shame.