JasonC - I follow and respect every word of your post, I simply remain unconvinced of a couple of the points. First of all, I am not convinced that learning caving under the guidance of a club will necessarily result in a caver being more careful. Here's why:
In south-central WV, USA, are a number of caves that are only traveled by Proper Cavers. They are locked, and some only accessible for survey or "scientific" trips. They are badly damaged; many speleothems broken, unnecessary flagging everywhere, calcite floors unnecessarily muddied and crushed, disorganized, illegible, and obsolete survey flagging everywhere, sculpted mud, old scaling poles lying about to rust, obsolete fixed aid and bolts.
In south-west VA, USA, are a number of caves undocumented by cavers, but well-known to locals. Many of these, especially those close to town, have very badly vandalized entrance areas, but some are very well-guarded and well cared for by their owners. Some of these owners have never been in their caves, but are careful about who they allow in. Others explore the cave themselves, and some have gone to great pains to attempt to "leave no trace". In general, and especially in remote sections of passage, the caves outside of the influence of the caving community are much more completely preserved.
So there is material evidence that some of the most experienced and institutionalized cavers, while not typically the sort to write in spray paint, are more blas?, and cause more damage than others (like myself, my father and my grandfather, who never knew that caving clubs existed until about ten years ago) who crafted their own cave conservation ethic from scratch.
I'm also unconvinced that caving is not aggressively marketed. It is obviously not marketed in the mainstream, in the same way as most other commercial products, but it is marketed by university clubs, and by a large number of individual cavers, who are constantly encouraged by NSS to "grow the sport", and who spread tales of their exploits on the internet and in person with something approaching evangelistic fervor.
