everlong, I was also just answering your question which you have posted more than once. DS, fair enough, doesn't whinge if he has had a little wee. He does if it is enough to make it swell a bit though. I go through tonnes of nappies for this reason. He also screams the place down from the moment he has a poo. I hope (pray) that this means he will toilet train much easier than his older sibling did.
I wasn't being funny to you, btw. Just answering your question from my experience.
And I know that the OP's DD didn't have a rash. I was, again, answering those who seem to not believe that a nasty bad rash can come from nowhere, and at the time on the bus, the OP would not of known unless she had checked IE removing the nappy.
Personally, I am one of those who does panic about others around me and fret. But, I just begrudge being told I should ask permission to do a job that every parent needs to do. It is natural. An adult wouldn't like it.
And what if they are selfish individuals who say no? Why should the child suffer because the adults can't simply just look away, open a window if necessary, and not breathe through their noses for a few minutes if they get so offended?
I used to hate it when I got on a bus and someone absolutely stank of BO. They didn't ask me if I minded. I just turned away, opened a nearby window if it wasn't cold, and didn't use my nose. Simple.
It may not be an ideal place to change a nappy, but it is much better than the child being in discomfort and crying, possibly leading to a sore bum. We seem to be expected to be considerate to others, but these others aren't being considerate to the poor child who has no other option. Adults on a bus do. Don't sniff/breathe through your nose, turn away, open window if necessary.