I guess. I was always ready to make that conscious effort - although because I was always going opposite the main traffic flow, I did not deal with a lot of super-crowded situations.
Generally I was more than welcome to 2 seats on the bus. There were times on the train where I had the entire coach.
But sometimes, there were situations where a big dopey lummox could have made concessions for a mom-dad-young-daughter.
In my opinion.
Not sure how much it comes across on the forum but I am a huge believer in courtesy in public. All pleasant and whatnot.