I'd like to see this rule altered to include a reciprocal obligation for the requesting player to show their hand. This would apply to those requesting players that do not voluntarily table their own cards but who have retained them. If the requesting player is granted the right to see another players hand then a reciprocal request must also be granted.
The idea that a requesting player must retain or have tabled his own hand is based in part on the idea of the
possibility of reciprocity and also to encourage showing down to increase the chance that indeed the player with the best hand wins it.
Automatic reciprocity is another matter. For example, what if the request is based on a reasonable suspicion of fouled hand or collusion. Must the requesting hand automatically be tabled in that situation?