At the last European Tour Rules Conference dec. 2012, I brought up this issue and specifically asked the referees who had attended
the recent USPGA events (at Kiawah 2012 all sand was through the green and in 2010 on Whistling Straits all sand was considered
to be a bunker) whether they saw an advantage for players to be able to ground the club whilst the ball lay in sand.
The answer was that all players basically stuck to their normal approach in a bunker and not grounding the club,
as this is obviously what they are trained to do. Personally, I think that moving a lot of sand on the backswing
could of course improve the lie, which would not be allowed by the rules even if grounding would be allowed,
as it occurs before the stroke and it would disrupt the backswing, which would in general not improve the result
of the subsequent stroke in my opinion.
This testing of the condition of the bunkers has kept me occupied before and I have asked several pro golfers,
whether they would learn more by e.g. being allowed to rake at will before a stroke. Their response usually is
that it won't give them much more than what they can already learn by just walking in the bunker and taking
their stance.
All in all, I think that as long as the lie itself cannot be improved, which will remain the case, however much
you let the player test the bunker, overall the quality of bunker play will for the majority of the players not
improve at all. The quality of the bunkers is a different matter and a different thread...
Jan