I am struck by the number of railcard users who encounter difficulties, whether or not of their own making, in matching their discounted tickets to valid railcards. I suggest that it would be a useful exercise - both to diligent users and to GBR as the future mega-TOC - to establish and maintain some sort of database linking every valid railcard, uniquely numbered, to its coverage, expiry date and holder id.
Then when a discounted ticket is bought, if the railcard is valid for the booked travel date its number would be printed on the ticket. A discounted ticket bought by or for someone who does not hold a valid card at the time of purchase would be provisional, only becoming valid if and when it is linked with a valid railcard number.
I accept that this would require sellers of rail tickets (online as well as paper) to have access to the railcard database as well as the fares database, and for railcards bought (like mine) at a ticket office to be accessible to sellers system-wide.
The current loophole allowing expired or non-existent railcards to get discounts would be closed (and buyers would be reminded of expiry), and forgeries and card sharing would be more easily detected.