Is there?
OK, I'm not aware of that.
I think, (and it is important to note this isn't anything negative about any individual(s) especially not bb21 or any TOC) that this proves how difficult the entire system CAN be when something like this appears to be in force but folk that work within the industry are yet to be informed about it.
Personally if i fell into the category and had said railcard i would be happy to use it with the 16 to 25 discount on it given the information that is available, as i am happy to politely explain to anyone who wishes to challenge it the information and show them an example. I can however fully understand why people may be worried about doing so. There are topics on this forum where someone has accidentally booked a ticket with the wrong railcard and has been forced to purchase a new full price walk up ticket or face prosecution so it will be quite unsettling for people who aren't aware of the rules and often read stories about people facing fines of hundreds of pounds for what comes across as a genuine mistake.
It is unfortunate but it is possible there will be instances on the network, we may or may not get to hear of them where someone will be forced to purchase a new ticket because of this because a member of staff isn't aware.
Slightly OT. The other week i wanted to excess a day return with a routing restriction to one with a different routing restriction due to disruption it meant i would be home earlier than waiting. My tickets were with a two together railcard but the excess was done with a 16 to 25 railcard to "save time" according to ticket office staff at Leeds. Gateline staff at Leeds were a little bit funny about it but let us through as it was obvious but they did briefly point out it was wrong. I had no issue on the train but a strict guard with people less familiar with the railway could have lead to problems due to the excess being
deliberately issued in error to save hassle by staff.