As mentioned in post #1, as a local Shrewsbury's gates are usual open from after 10PM until closing time. Both the TFW and WMR services between Shrewsbury and Birmingham don't get any ticket checks particularly imbetween Wolverhampton and Birmingham (though the once I did and the 2 teenagers in the seats Infront got the penalty fare as they didn't pay because they expected no ticket inspection.)
Also if you hop on the front carriage of any Cambrian services between Porthmadog and Tywyn you are fine because by the time the conductor has made it to the inter-carriage gangway he has to go back to the rear of the train for the local door.
Just to follow-up that the historical BR-era ticketing system that is widely still in use today is designed to maxinise revenue.
First thing to remember is that Off Peak Day Returns normally cost 10p more than a single.
Then on a normal day return there are six opportunities to check a ticket:
- At the origin station before the outward journey starts
- On the train during the outward journey
- At the destination station at the completion of the outward journey
- At the destination before the return journey starts
- On the train during the return journey
- At the origin station at the completion of the return journey
As long as
one of these six checks takes place then the railway will basically collect its revenue.