Ok sure - but the validity can’t be backdated, so previous tickets would still be invalid, no? If not, again, what’s the incentive to stop people abusing that?
As for the latter, I think I recall a recent thread about an “accidental” wrong licence number being entered to renew a railcard. How are we supposed to know how people have obtained railcards on board if all the details look correct? Unless it’s a screenshotted railcard with an altered name/photo etc, which would be an easier spot depending on the photoshop skills. A handful of times I’ve seen people using senior railcard tickets, when they’re in their 30s etc but then show Network Railcards, which aren’t valid on the network that I work. This is obviously an easier spot.
I really am open to changing my approach to passengers on board and I’m trying to keep an open mind here so please don’t see this as me being argumentative with you. I do genuinely appreciate your opinion. Maybe the railway as whole should be too. But there still needs to be deterrents in place.