This seems to be quite typical of Northern, if you turn up they will withdraw or settle quite happily. Seems a very shady way to go about prosecutions as it doesn’t seem like you presented any new evidence.
Please do follow up the complaint. Tristan Kirk at the Evening Standard may also be interested in your experience.
But as has so often been said on here what would be a better process that didnt also give the persistent fare evader carte blanche to continue.
How many of those at the court have failed to engage with Northern? If they do not engage what action should Northern take? By summoning them to court, Northern has the opportunity to settle with some of those (possibly the same as they would have done if they had engaged) and withdraw others (possibly the same as they would have done if they had engaged). Obviously the Northern representative has to make quick decisions based on what he can see at the time. He will have a summary of the cases with him / her and will be able to see those who have / havent engaged and the strength of the arguments of those who have engaged but to that point have been rejected by Northern.
I do not defend Northern's apparent heavy handedness but until someone comes up with a better system then it is what we are faced with.
Undoubtedly there will be a small minority of cases which Northern has got wrong and they do need to look at these and see if there is a systemic problem. Certainly disruption seems to create problems with advance tickets and single operator only tickets and whether the rules have been waived.
Messages such as you must have a valid ticket before you board the train (acknowledging there are certain circumstances where this is not required) and you must have a valid railcard if you claim the railcard discount need to be repeated time and time again. Perhaps the tocs also need to remind app bookers to check their railcard validity and whether it is auto applied before making a booking.