I'm not at all clear on the point you are making. But I do understand exactly what the announcements at Euston and on the train mean.
Sorry, wasn't suggesting that at all (my bold).
What I was trying to write was that, in the case of short platforms you can only
alight from specific cars. but you can move to those specific cars from the non-platformed ones easily and before arrival. The announcements only refer to
boarding or
travelling in specific cars. While we understand the underlying meaning a passenger not well acquainted with railways may think that the announcement that passengers should
board the front four coaches (for example) for their destination means just that - and if they board the fifth they will in some way or other not be able to alight.
Blimey, I think we're now approaching peak first world problem territory.
The obvious solution is to make all coaches first class.
Fantastic line in A Very British Coup: "Are you going to get rid of first class, Prime Minister? No, I'm going to get rid of second class."
As above, my post was connected to the loose language used in announcements inaccurately saying that you shouldn't travel in specific coaches instead of the fact that you can't alight from them.