Why is she standing?

An old woman gets onto the tram. The tram is full. All seats are taken. Nobody wants to give up their seat for her. She sadly says:
- There is no one with good manners these days.
And one of the seated passengers answers her:
- There are a lot of people with good manners. There just aren't enough trams.

Which reason does make her stand up? Why is the woman standing in a tram?

The An old woman gets into on the a tram. The tram is full. All the seats are taken. Nobody wants to give to her a seat. She sadly says:
- Isn't there is not anybody with good manners in our time these days.
And One of the sitting passengers answers her:
- There are a lot people with good manners. There trams are not enough trams.