Substitute the daytime London Midland service from London Euston to Birmingham New Street and Crewe, two lots of four-car 350s, splitting at Northampton, on Saturdays - same thing.
I've been sat there, listening to repeated announcements on board and booming in from the platform, watched apparently sentient people look at the screens, get on board, stand underneath the scrolling display unit and STILL ask 'is this the Birmingham train?'. I know not everyone travels frequently, and not everyone is familiar with such operating procedures, but, really, some people just aren't safe to be out on their own.....
Now, there's no excuse for staff being rude, but I can thus understand why they must be sorely tempted.