We are exhorted to keep luggage with us at all times
How?
Not all commuters
Some of us go to visit family or others or go on holiday with LUGGAGE
At 5'2" cannot reach overhead space even if case would fit
Not all carriages have luggage space
Not really enough room under seat in front or between seat and end of carriage
Do not want to block aisle
On seat next to me if there is one, causing others to stand?
Become a nudist at my destination?
I think the general concensus regarding luggage is that you need to be able to identify it all times for security reasons. Not ideal if it is not near you.
Heard what I thought was a valid argument from a Chinese lady on the train last week, she struggled to get her luggage up on the overhead rack just as the train manager walked through, he told her, quite nastily, not to put it there and to take it down to the luggage space by the sliding door to the carriage, she was trying to explain that she had heard the announcement about keeping it with you at all times. Poor lady was very confused.