How about you describe what the banner says. Not many people are going to be bothered to fire up the game to hunt for a possible Easter egg without some kind of indication first.
At least if you tell what the banner says, we could find it if we're interested, or refute it without needing to hunt for it ourselves.
I've noticed a lot of so called Easter eggs in this game are really tenuous and come from people who have a poor historical and cultural awareness and are grasping at straws, like "OMG that character has to be a Bioshock reference because I wasn't aware of that extremely common surname before I played Bioshock".
Also, please don't let this Easter egg be something like "Team Bondi must be really big Jack Black fans for naming the 'Gulliver's Travel Agency' after his film ", or "John Marston is in L.A. Noire because I found a hat in a bin".
