I would not have paid up either. I am quite surprised that so many people on board gave over that amount of money so easily. Poor show on the guard concerned, it would have been most clear to him that something was wrong.
To play devil's advocate, if I had a pound for every time someone travelling on an Advance on the wrong train claimed to do so because of alleged wrong (often misheard) announcements / the 'man on the platform' told them to / it's someone else's fault, I would be on a beach in sunkissed Waikiki, not umpiring amateur drunk wrestling on the 2330 to Cardiff for a living.
I suppose the difference is I'm more inclined to give the benefit of the doubt where appropriate, because sometimes it's just good to be
nice to people. Some people are less lenient.
My point is you come across that many chancers with the same excuses that it's really easy to become cynical.
Also, if you do the job, you'll understand that a large number of people actually can be wrong. When I used to work the 2334 Reading-Gatwick on a Friday or Saturday I would announce at least 5 times prior to departure, and get the platform staff to announce that the train doesn't call at Wokingham (it does Monday-Thursday), but would invariably get at least 10 people getting incredibly angry that 'nobody told them'. I'm not even talking about the inevitable drunks.
As I say, its easy to be cynical, and once you've charged one person in a situation, a lot of people will (being human) carry on to save face.
Just trying to balance this with the 'crucify and give the guard 40 lashes for making an error of judgement' point of view.