On Wed, 9 Aug 2017 09:37:21 -0700 (PDT), Paul Corfield
wrote:

On Tuesday, 8 August 2017 01:00:38 UTC+1, wrote:

It's the same as for Oyster but the flag would be placed on the Oyster
account instead of on the individual card. [...]

I know that is a theoretical possibility but take a step back as to how online accountd work. The card holder logs on and sets up the account themselves. If they wish to add bank card details to their account to give access to extra information facilities if they use their bank card for travel then that is their choice entirely. TfL hold the data but never enter it or change it.

I can think of a way to do it. The customer has their Railcard
checked by someone at the station who verifies it in whatever way they
do now. The LUL person then gets the ticket machine (or to save £££s,
a hand-held device with printer) to generate a unique (use once,
time-limited) code that is printed out on normal ticket or receipt
stock. The code, er, encodes the Railcard type and end date, possibly
the card number.

This unique code is then entered on the TfL site. If the ticket
machines can print images, then a QR code could be scanned and
uploaded instead, or the URL found in it simply accessed. Entry of
the code associates the Railcard with the online account and different
fares/caps are charged accordingly, to any cards registered there. I
think it is quite reasonable to expect users to register to get a
discount so I don't see this to be a problem.

And to think that TfL wouldn't give me a job!

Richard.