An observation as someone who uses public transportation on multiple continents: Europeans will, almost without fail, use the exit at the middle of the bus while I'd say close to half of Americans will insist of using the entrance at the front of the bus to get off even if they have to walk past the exit to get to it. #Rude
@michaeljoseph Oh, that's likely because of school buses. School buses only have one non-emergency door, which is in the front so the driver can monitor kids getting on and off.
Since a good chunk of Americans only ever experience school buses, it makes sense that we'd do what we've always done out of habit until confronted.
Same logic can be applied to trains, since we usually don't have access to trains. Elevators to a lesser extent, since we do use them but infrequently. Last time I used one was in a hospital I think. 
It's typically rich Americans that get to travel, so I don't know for sure they won't Karen out... But for most people a tap on the shoulder and a "we exit from the middle" should be all that's needed to get them to fall in line.