RJ Daley
I had not thought about the grounding helping you judge sand, however I would think 90% of the players would not know what to do that information once they gathered it from grounding the club. Furthermore, walking in the bunker, and working your feet into the sand when taking your stance gives you some insight.
Nicklaus reportedly never grounded his club anywhere through the green. It prevented him from dragging the club on the back swing, kept him loose on the back swing, and if the ball moved he wouldn't be penalized cause the club is not grounded.
Mike says when in doubt don't ground the club, but I believe most golfers do not pay that close attention to the rules. Most are respective of the game's rules for honesty, but I think player's just feel that a little infraction here and there is no big deal, or they may be ignorant of the rules. So Mike's declaration is probably how some of us would deal with it, but do not expect it from most of the other players you encounter on the course. I remember being in a particularly lousy part of the fairway at Sand Hills, the turf was severely damaged coming out of winter, and in deference to the superintendent I probably should have moved my ball, but it was not marked ground under repair so I played away, I saw no choice, even though it was just a friendly match. Someone noticed and commented. I say this not to claim high ground on the issue but just to illustrate the need to have simple, clear cut rules about a situation like the bunker or waste depicted in the picture. Either I get to ground in all the hazards or I do not, do not make something like that a judgement call. Allowing the grounding of the club in all bunkers I think gives the architect a lot more flexibility in the bunkering design. If not, then you always have the rules committee, or some stickler for that rule looking over your shoulder telling you that design is no good because people do not know whether they can ground or not. It limits creativity.