In message , at 16:19:00 on Wed, 3 Sep
2014, Neil Williams remarked:
Although you need to carry the railcard with you, to prove it's
really the entitled person travelling and not an unentitled person
you lent the card to.

To get checked approximately once every blue moon if ever.

If it's never checked then even more reason not to worry. After all, it
doesn't matter how much you check that the person stood in front of you
is a genuine railcard holder, if five minutes later they give the Oyster
card to their flatmate (rinse and repeat).
--
Roland Perry