Admittedly this is the first I've heard of this but it strikes me as people trying to cash-in on the "Jesus' life and the mysteries that surround it" craze (Priory of Sion, Gospel of Judas etc.) that has sprung up since that damn DiVinci Code came out.
Wow. That's pretty spectacular. I hope nobody was injured. I remember going on a family canoe/camping trip there when I was a youngin', and if recollection serves, there's not much in the way of tracking who is in the area, and where they're at.