nothing gets by me, ever
Unites Airlines chose a snippet of Gershwin's Rhapsody in Blue as their theme music, for obvious reasons*. It plays several times on every flight.
A version of it also seems to be playing in the tunnel between the B and C concourses at Chicago's Ohare airport**. I'm not sure if that's coincidence or not -- did United pay the airport to play it, or did they pick it independently? These are important questions.
But my point, which I do have, is that it's possible to be intimately familiar with United's theme music, to the point where you find it quite irritating, and not be aware that it's the famous Rhapsody in Blue. You could, for example, be 42 years old and hear your daughter playing it on the piano and think "How cute, she's picked out the melody to that United Airlines song" and then have to have her explain that it's actually a major composition whose name you know, but because you're such a Philistine, you've never actually listened to.
I'm not necessarily saying this happened, but I'm not saying it didn't, either. I'm just saying it could.
*because it sounds like being happy in the sky. and because Smoke on the Water doesn't really set the proper mood for nervous travelers...
**why is Ohare's airport code ORD? that makes no sense to me...