Last year I went to Newcastle and on departure from York, the LNER TM told two gentlemen (clearly unfamiliar with the system) who'd just bought tickets from the machines that their tickets were TPE only, and she would need to sell them new tickets at the full price. Similar type of train with similar passenger comfort levels, similar journey times, the LNER train was very lightly loaded, and both trains run by OLR. And yet on a technicality both of these gentlemen were then £40 out of pocket, each, over a fare difference of £3.50.
After that kind of experience those gentlemen will likely never want to get the train again, and will drive in future.
So who exactly benefits from this farce? Certainly not anyone who wants to see more people travelling by train.