Split tickets are a loophole, they are not an official option, buying them is exploiting a loophole. They alter so much about a ticket and a journey and validity. To offer them often would only benefit this forum as the amount of people in the dispute forum would skyrocket.
If someone asks me for the cheapest ticket from Thetford to London including the underground they will be offered an Off Peak Travelcard, its the ticket they have requested and is the cheapest. I'm not going to (or capable of) memorising every possible split. Or remembering which split works only in the peaks but not off peak or visa versa.
Nope they most certainly are not a loophole as they are explicitly allowed by the terms of carriage. Hell there have been cases of people believing they HAVE to do split ticketing because they thought they couldn't by mainline tickets on their branch line bit of the journey.
However, that does not mean I think ticket offices should have to specifically explain and work out splits for all customers. More that as long are people are aware that it is an option but that the customer has to do the legwork so to speak, then I'd be happy with that situation. It is just at the moment it really feels to be like a bit of a dirty secret.
The way you've worded this suggests you think not advising of splits IS a way for TOCs to hide cheaper fares. I don't really think that's fair - as a previous poster commented, you can't realistically expect staff to check every combination of tickets for every possible journey. I know of some local splits that come up fairly often but the other day I was asked for a new one. I have no problem whatsoever selling them but to be accused of wilfully withholding cheaper fares by not offering ticket combinations I don't even know exist seems a bit rich.
That's not to say that I don't think the existing fares structure is complex and frustrating, just so we're clear.
As above, I am certainly not expecting that. But what I would like is for the very fact that splits can work out cheaper to be actually known to the public. Right now it does seem like a bit of an industry dirty secret, and it is only because of news articles like this that people outside of the industry / forums like this one know about.
You are assuming people would actually read it, I have little faith in that approach.
Perhaps selling them 5 or 10 minutes before might be okay, as this would allow tickets to be bought for trains departing close to the time restriction, but not too early to allow much misuse.
The problem with that is that you are still punishing genuine passengers. Certainly at some stations where there is just a single ticket machine. Surely if a manned ticket booth would sell an off peak ticket at peak time for later use then the rules should be a ticket machine does aswell. In the past I've got around the restriction by buying the ticket on my phone while travelling to the station then picking it up, so if I can do that then why on earth won't the machine itself sell the exact same ticket to me? It literally makes no sense. I do get the argument about people claiming they didn't see the restriction etc, but the exact same issue is there for online / app bookings so I'm not sure that is a convincing reason.