Do you mean the general instruction which obliges someone to actively go and find the guard? Or the specific instruction mentioned in the original tweet in this thread? Or the sign at Chester?
Let's get back to basics. The Regulation of the Railways Act states:
Railway Bylaw 18 states:
The National Rail Conditions of Travel essentially repeats these, with a bit more info about what to where Permit to Travel machines are installed, and also clarifies that anyone with a disability who cannot access the facilities is able to travel without a ticket. It then goes on to state that if any of the above 3 conditions apply:
And that is, to the best of my knowledge, it in terms of what the law has to say about ticketless travel.
From this, we can add one further clarification. Railway legislation rarely goes beyond Magistrates Court and as these don't set precedents, then there is rarely anything set. There are a few precedents but the main one cited in relation to paying once you've started travelling in relation to the Regulation of the Railways Act is Corbyn v Saunders (1978). But you can see the summary of this in the Weekly Law Reports here:
So Corbyn is only useful in determining that intent is proven when passing an opportunity to pay at the arrival station, although it has also been cited I think to support the argument that intent is shown where someone has passed an opportunity to pay when boarding too, and I think that's a reasonable argument. What it doesn't really get into is anything about buying on the train itself.
As rs101 says, the question doesn't seem to make much sense. If the law doesn't state that you need to find a guard, then, you do not need to find the guard. There doesn't need to be a sentence saying "you don't need to find the guard".
The only scope really for argument is in terms of that statement in the NRCOT that "you must, as soon as you are reasonably able, buy an appropriate Ticket to complete your journey...This means that you should buy a ticket from the conductor on the train if there is one available" What counts as 'reasonable' or 'available' is not defined and can probably only be ascertained situationally. As has been said, it would be unreasonable for someone to seek a guard on a standing-room only 12 carriage train. And it would be unreasonable to ignore a guard walking down a train saying "anyone needs a ticket". What happens in cases which fall between these binaries would come down to an argument in court, but what can't be said is that all passengers must always seek out the guard.
In terms of the instruction at Chester and the Tweet: the law permits notices at stations or "an authorised person" to give permission to travel without a ticket, but it doesn't give either those notices or people the authority to demand that a ticket must be purchased on the train. Therefore I don't see how those specific instructions can carry legal force to oblige you to buy on the train if you are not reasonably able to do so.
many times boarding Merseyrail trains, usually in the Liverpool loop but I have also seen them out Walton way.
