A feature that I find odd in this (and some other recent threads) is that if a conductor is on duty at the station for the purpose of selling tickets, and a passenger goes to buy one, why is it also considered necessary for a 'minder' to intervene and question the transaction. Of course I know that there will be people who try to cheat, but the fact of approaching the conductor shows intent to pay (even if in breach of the 'earliest opportunity' rule. Treating passengers as potentially criminal until they prove otherwise does not do the railway any favours.