Regarding the OP, I don't think anyone was referring to technical diving, caves, or penetration diving. What I said was "I believe if two advanced divers want to go into a cavern in-sight of the surface, with proper equipment and exercising good judgement, I don't think they are "tempting fate at all."
Cavern diving is by definition, a form of recreational diving. This means among other things, that divers can obtain recreational-level Specialty Diver certifications in cavern diving from open-water training agencies such as NAUI, PADI, SDI, ACUC and SSI.
Others may argue, Cavern diving is the exploration of permanent, naturally occurring overhead environments while remaining within sight of their entrances. As you will note, my comment mentioned within sight of the surface which entails little or no penetration whatsoever. For this type of diving, a "cavern specialty" is not recommended by any diving certification agency of which I'm aware. It's analogous to non-penetration wreck diving.
As an Instructor I promote and have taught a number of specialties (Cavern diving included). If any diver decides to penetrate a wreck, cavern, pipeline, anything, further training is required. I do not however take a "you're gonna die" attitude if someone pokes his head into a cavern or a wreck. It's all about diving within your capabilities and exercising good common sense.
I think what DCBC is saying is :
if you've got the skills and the judgement, a 10 foot penetration shouldnt kill you.
A cavern is just another environmental hazard to be wary about. OW divers in crystal clear waters can die getting tangled up in fishing lines just as easily. In EVERY scenario in diving, you need good judgement to stay alive. If you've got bad judgement, you're just an accident waiting to happen.
Some divers out there might be good enough to do a short penetration in a spacious enough non silty cavern without killing themselves. I've never done this but if I had the chance to, I probably would unless my instincts kicked in before I entered. I highly doubt that I would die, but I'm sure that there has been at least one Darwin award winner who managed to kill themselves in the very spot.
I don't think cavern diving without sufficient training should ever be promoted. If a diver chooses to do it himself after much deliberation, fine its his life. Giving false hope to a newly minted OW diver, bad idea.
Perhaps DCBC's words could be taken either way depending on the reader. To me, he said be smart, be sensible, a cavern course cert card doesnt mean you're invulnerable. To others, maybe it sounded like go ahead little boy, swim into the cavern to your death.
shrug.