I'll start this by saying I'm 25 and don't have kids, so I honestly don't have any preconceptions/prejudices about child behaviour.
I'm currently living in London and I went out for dinner with a friend tonight. I'm on the night bus home - for reference, it's 20 to 1am. There are 4 kids who are definitely under 5 on the downstairs floor of the bus. None are playing up - they're all adorable, actually! - but AIBU for thinking that it's not normal to have an under 5 out past 9pm??