I totally oppose this. People should be excessed to the appropriate fare. The old PF rules used to allow people to be given a penalty fare (in PF areas of course) for being on a time restricted ticket at an invalid time, but this was changed a few years ago.In my opinion they should sell them at any time of the day and the use of them before the appropriate time penalised heavily.
Quite how anyone can ask for passengers to be penalised heavily when the restrictions are incredibly complex, is beyond my comprehension, so we'll have to agree to disagree on that point.
Many people mistakenly think that off peak always starts at a certain time (e.g. someone in EMT or LM territory who usually does local journeys would think that time is 0900) and if they visit an unusual area, why should they not take the ATOC claim that the name "off peak" describes when they can use their ticket (ie, if one is valid after 9am, they must all be) at face value? Does someone who believes the ATOC spin deserve to be heavily penalised?
As for the screens, there is no such thing as a "peak" ticket, and some Off Peak tickets are valid. However there is no point contacting First about this issue any longer, it now needs to be escalated to the DfT/Passenger Focus/ATOC/Watchdog/whatever. The book needs to be thrown at them quite frankly.