I suppose this could have gone to games but I’ll try it here.
I think this is the pattern. The Baltimore Orioles are sometimes just referred to as the “O’s”. Fans there have developed the habit of loudly singing only the “oh” in the line “Oh say can you see”. I’ve heard that a smilar thing happens with “Brave” at Atlanta baseball games.
I’ve heard at other events (Viginia Tech football, Washington Caps hockey) the fans also do the loud “Oh”.
I guess my first question is if my theory of why the loud “Oh” is correct? If so, does that mean that people at those other events just heard it and misunderstood the meaning and now just look like idiots when they sing “Oh” at a Redskins game, etc?
Singing the loud “oh” now safely qualifies as a Baltimore/Washington area tradition. In the years between the Colts and Senators moving out and the Ravens and Nationals coming in, Baltimore and Washington had a shared sporting identity. Hell, even the Washington Wizards were once the Baltimore Bullets. I am pretty sure the people singing “oh” at the Redskins and Capitals games know its Orioles origins.
I’m graduated nearly 15 years and I still have to think about it not to do it. Which gives some context to why some still emphasize the “Oh!” during Nats games. But don’t worry – when I see someone do it I give 'em a look.
My brother went to UND, and apparently the tradition there is to sing the last line of the National Anthem as “and the home of the Sioux.” He’s done it for years.