Incident in the U-Bahn

A few hours ago, I was riding in the U-Bahn (the U2, actually) when a tour group of about a dozen college-aged Americans got on. I could tell they were American, even though I was sitting at the opposite end of the car, becuase they were talking quite voluably - Americans have a well-deserved reputation for being rather inappropriately loud in public places. I wonder sometimes if it isn't some odd result of our Puritanical/Wild West thing about personal space. Europeans are used to living in close quarters, so if they're talking to one another on the train, they tend to lean towards each other and speak softly, whereas Americans tend to keep their distance and bray. I find myself doing the same thing when I'm with American friends, if I'm not being careful.

Anyway, at one point, there was a lull in the conversation, leaving the car silent. Then, one of the young men in the group started whistling what was very clearly "Hail to the Chief."

Did that just happen to be the song in his head at the time? Or was it some sort of dig? I'm going to wonder about this.