About ten years ago we were in the Dominican Republic. Bunch of us riding in the back of a truck going on some trail riding excursion (horseback). A fairly inebriated lady yelled out "GO WAR EAGLES!!". Seeing as the rest of us were from Canada, Germany, Italy, United Kingdom, none of us knew what she was yelling about. She was shocked...she said something like "What the hell? Don't y'all watch football?
Back in the 1980s I moved to Montgomery, AL. I learned to carry two t-shirts in the Truck. One for Auburn and one for Alabama.
When I pulled up to a new bar I checked out the bumpers of the pickup trucks in the parking lot. In this way I made sure I wasn't inappropriately attired and had my comments aligned with the occasion.