True, of course, but you haven't really responded to the point that PenaltyFines and others have made: it may indeed be a 'strict liability' issue to have a ticket but the onus is nonetheless on THEM to prove that liability in the first place, which is pretty hard to do standing somewhere outside the station.
Oh I am sorry if I have not made myself clear.
A passenger completing a journey at a station is expected to either (a) pass through a ticket operated barrier, pass through a barrier line (something different) - which may or may not be unmanned, or pass through a station which does not have a barrier at all.
Now it would seem reasonable that a passenger in possession of a ticket,which has not been collected, would have that ticket on their person and thus would be able to produce it immediately on request.
Now they COULD have thrown it away on the station (littering) or thrown it into a bin, in either case it could be quickly recovered.
Until a person completes their journey, they can expect that at some time they may be asked to produce the ticket for inspection so as to be able to demonstrate that they actually HAVE paid. This is no different to being in a shop with an item which was purchased before a customer leaves a store. For the sake of clarity, the journey is completed when the passenger leaves Railway premises. In practice we accept that the journey ends when the passenger passes through a ticket barrier, past the defined barrier line, or in some cases leaves the platform. RPIs are generally pragmatic people who do not enter the job as a means of antagonising the travelling public, and will use their judgement. Stopping people immediately outside of the station simply demonstrates without any discord, intent to avoid payment UNLESS a passenger specifically approaches the RPI for the purpose of paying the fare.
That said Railway Byelaws make it an offence to be on a train without a ticket in specific situations. Situations which are not clearly defined will then fall under the 1889 Act once the passenger has attempted to leave the station.
I see being asked to produce evidence of having purchased a ticket on departing the station no differently to being asked to produce a sales receipt in the event of an item in your bag setting off a store alarm. Do people start arguing with the security guard ? No, not in my experience unless they are trying to thieve.
The Regulation of Railways Act 1889 is quite clear in that it is the responsibility of the passenger to produce a valid ticket when asked to do so. I really do not see what the issue is here, other than this modern attitude towards questioning even the most reasonable of request when made by staff in uniform.
The 1889 Act makes quite clear the consequences of not being able to produce a ticket.
I believe that the Conditions of Carriage direct passengers to retain their tickets until they have completed their journey. This is so as to get around this issue.
An RPI will NOT be asking someone to produce a ticket somewhere down the High St. They will be operating from Railway premises in practically every case, and when stood outside of the station will again almost always be on Railway Property. Even if they are not they are still entitled under the 1889 Act to request a ticket.
Whilst you use the term "Strict Liability" that is not appropriate.
Perhaps the act of bothering a fare-paying passenger beyond the station is simply not reasonable; I think my reaction would have been exactly the same, possibly exacerbated by a perception that there are too many heavy-handed RPI types out there. As my grandmother used to say, "If you have a hammer, everything looks like a nail"; if you're an RPI perhaps everyone looks suspicious?
The OP was asked on exiting the station.
If you feel that there are many "heavy handed RPI types" then maybe a clue as to why can be read in the second sentence of the OPs first post. Had the OP done so in my time (when I would have had BTP around almost certainly) then they would have been having a word at the very least, as I would never tolerate under any circumstances my staff being abused by passengers in such a manner. Make of that how you wish, but I finally gave up frontline duties because of the hostile attitudes of passengers, which made the job so much harder. I admire those who can deal with such morons day in, day out, as I found myself becoming less and less tolerant with them as time went on.
By the way I do not condone staff being abusive or heavy handed but in many cases staff become conditioned to dealing with what is seen as "normal" aggressive passenger behaviour. Again the OP first post suggests why this happens.