tncaver, et al,
Before we build up a head of steam again about proof or no proof, you should be aware of the study just presented by Joe Okoniewski, NYDEC, at the Pittsburgh WNS Symposium. I've described it at length on another forum:
http://www.forums.caves.org/viewtopic.php?f=1&t=10284&p=87994#p87994This is now well-circulated within the management community. It does demonstrate that the potential is there, although it acknowledges that it does not show all the steps for human-borne transmission. So, we can bring spores out of an infected site unintentionally, as well as intentionally, which we already knew. It certainly speaks to the wisdom of cleaning and disinfecting, and to not using gear from WNS sites in unaffected sites.
Re: the idea of using cave registers to document caver traffic without WNS, I think that's a great idea. Similarly, look at commercial cave attendance numbers. Maybe, just maybe, the Howe Cave hypothesis is correct, but think of how many millions of other possible transmittals have gone by the wayside without occurring. While I don't believe we'll ever prove that human transmission has not happened, it clearly is not something that happens easily.