mycroft, on 2022-September-28, 10:25, said:
The reason for this is the same as the reason why the opponents don't have to and should not remind declarer about the previous play, and why dummy shouldn't be showing declarer their card after it is quitted to "prove" that she is on the board/in hand. The director certainly shouldn't be assisting declarer with her memory. This is also why, if called for an established revoke, the director will not ask for it to be proven before the end of the hand (and this director gets very upset when he gets to a table with the last 3 tricks turned face up. Sure, you found the revoke this time, but what if there wasn't one, declarer just wanted to see the last three tricks?)
It is quite feasible for director to peek at the down side of quitted tricks with nobody but the owner of those cards able to share the view, at least with our current large tables.