I am utterly amazed that we are debating this, in some cases, with utterly undeserved ferocity.
A woman we don't know caused a fuss with another woman we don't know on a train we don't travel on.
An opinion on the big picture, fine, but the willingness endlessly to drill down into the finer points of Southern Rail's fare and passenger policy is frankly baffling!
I repeat - the inbuilt snobbery of the rail ticket 'class' system brings out the very worst in people who care about such redundant nonsense.
The bottom line is, a woman with a baby needed a seat on a crowded train - I think no-one really needs to look further than that, including the reprehensible snob who rowed with her about it.