This brief interview is pretty interesting:
http://www.npr.org/2011/11/26/142701523/unconquered-explores-an-isolated-amazon-tribe
Also see on that page a link to an excerpt from Wallace’s book.
Hm, they left gifts of metal tools to this uncontacted tribe? I hope they knew this tribe already has traded for some.
If this tribe shoots first and asks questions later, my “plan Y” of canoing up the Amazon until I find a tribe that will take me (“plan Z”: give up and embrace Civ) might not work out well.