Some
TOCs▸ have some restrictions in their
TVMs▸ , e.g. South West Trains. On various tickets it will actually tell you the availability times. Even this is incomplete and often incorrect.
One of the worst examples I saw earlier this year was at Liverpool Street. Helping a friend to buy a ticket to Cambridge or Huntingdon or somewhere nearby on a Friday. I hadn't pre-planned that I'd be asked for fares assistance after a few pints and only had about 2 minutes until the train departed. I was presented with a selection of ticket types but no restrictions so no clue what was valid. Then I was asked to choose "LER Only" or "Any Permitted". Considering London Eastern Railway Ltd no longer operate trains (they are operated by Abellio Greater Anglia Ltd), I assume this ticket is useless*.
Sadly I don't have any photographs or videos, but the Italian ticket machines were excellent. They operated with a very similar interface to the Trenitalia website, where you select a "solution" (i.e. itinerary) then are presented with up to three fares for that specific service: base, economy and super economy. They can make seat reservations and you can choose a seat next to someone who already has a reservation, if available. Sadly they couldn't sell tickets if the itinerary involved a Deutsche Bahn service, even if wholly within Italy. And don't get me started on the Regionale and Regionale Veloce services.....
* = Of course, I am joking. The ticket actually printed as "GRT ANG TRNSONLY". Now why didn't it say that on the screen in the first place.