It's one of those things that is not legislated but will be agreed upon by the ORR. Google found a thread here from a rail enthuisiasts / workers forum, the changes seem to have been communicated to staff working in ticket offices...
I don't care. The solution to a problem isn't to punish ordinary people.
The abuse only happens in any event because of the dreadful reliability of the railway. Address that.
Stoke tweaked a few things at half time and made it much more difficult for us to play, you have to credit the opposition a bit it's not all about us dropping off.
Both teams got what we deserved in the end anyway.