I cave dive with no ditchable weight (no weight at all, actually, other than my tanks). I don't worry about it, because I cannot really imagine a circumstance where ditching weights in a cave would be helpful.
But I think, after three years of reading this board and incident reports elsewhere, that new divers ought to have some ditchable weight, not to ditch at depth, but for the SURFACE. The simple fact is that, if you are too positive to sink, it is difficult (but not impossible) to drown. Someone exhausted or panic stricken can very easily be rendered unsinkable by the removal of sufficient weight. Then the rescuer can sit off a ways in safety, and wait for the person to wind down enough to be safely helped. There are way too many stories (like this most recent one in Florida) where divers made it to the surface, only to disappear again. If they had been able to become positive, perhaps that would not have happened.
But I think, after three years of reading this board and incident reports elsewhere, that new divers ought to have some ditchable weight, not to ditch at depth, but for the SURFACE. The simple fact is that, if you are too positive to sink, it is difficult (but not impossible) to drown. Someone exhausted or panic stricken can very easily be rendered unsinkable by the removal of sufficient weight. Then the rescuer can sit off a ways in safety, and wait for the person to wind down enough to be safely helped. There are way too many stories (like this most recent one in Florida) where divers made it to the surface, only to disappear again. If they had been able to become positive, perhaps that would not have happened.