As I guessed, a can of worms but useful and well thought out points are being made. Caves can appear to be permanent and fixed finite things, but a moment of reflection shows they are highly dynamic places that constantly change (the speed of change can be very slow to our monkey brains...). Personally, I would love to do a 3 Deeps, or a 3 Peaks / 3 Pots, but I would not do it for charity because 1) I cant be bothered with all the hassle and 2) Charity is something I deal with in other ways - my choice. I have done a 3 Peaks and found it very rewarding, but tiring. Sponsorship would, for me, have detracted from the experience. If others would be doing these trips anyway, and can go the extra mile to raise the cash as well, then good luck to them. The cave environment can be very fragile, but so are other environments. The modern society we live however means that a living can be made from such places without excessive damage, unlike mining, quarrying or taking stal for artificial grottos as has been the case in the past. The days of being frowned upon for "being in trade" are I hope long gone, but ethical best practice should always be advocated.
(As an aside, the best way to preseve wildlife is to keep it in formaldehyde, to conserve it is much more difficult. The presevation / conservation debate is something else entirely...)