Gareth, all of what you say in
#65 is undoubtedly right.
But you are still avoiding answering the question about the honest customer.
In a penalty fare area, what are the 'exceptional circumstances' in which authority to travel may be given? If they are told that exceptional circumstances (undefined) exist, an honest customer may genuinely think that 'something wrong with the app' is one of those exceptional circumstances.
It certainly benefits the railway industry to be able to just tell customers to travel without a ticket or beyond their ticket's validity in exceptional (for the railway) circumstances. But does it benefit the customer when an honest mistake or misunderstanding could lead to a penalty or worse?
Surely authority to travel needs to be documented and traceable, for the assurance of both parties?