But effectively they could still do that at the point of use if they wanted to!

Recall, before ID was mandated, you would turn up and state your name and address which would be checked against the electoral roll by the officer.

Therefore ...

If someone 18–59 turns up with a photo Oyster card, you could, if you wanted to:

    1. Check their face against the photo on the card
    2. Check their name and date of birth on the card against the name and date of birth on the electoral roll.