The ACBL Laws Commission called for measures against cheating:
The recent spate of accusations of high level cheating has rocked the bridge world. In several of these cases, a player – as dummy – is alleged to have asked to look at a defender’s hand and then signaled the location of a key card to the declarer.
This is the relevant law: 43A2(c) Dummy may not, on his own initiative, look at the face of a card in either defender’s hand.
At its meeting here in Denver, the ACBL Laws Commission voted to request the WBF Laws Committee to strengthen this provision in the next version of the laws as follows:
43A2(c) Dummy may not look at the face of a card in either defender’s hand. A defender may not show dummy his hand.
While this change does not yet have the force of law, the ACBL Laws Commission requests players to act as though it did. There is no reason for a defender to show dummy his hand, and it can lead to unnecessary suspicion of wrongdoing when, for instance, declarer subsequently makes an inspired guess.
***
Source: ACBL