North Sentinel Island

Last week I read a really interesting article about an american christian missionary, who travelled all the way from the US to a super tiny island near India, called North Sentinel Island. There, this gringo, called John Allen Chau, pretended to evangelize the people know as Sentinelese. Long story made short, Chau managed to get to the island being ferried by some fishermen, who where the last ones to ever see him alive. This kind of story has repeated many times since "world culture" made contact with the Sentinelese, they remain to be nearly the last untouched and vastly unknown culture in the whole world.
Their unique formula to be left alone is indeed, pretty simple, they tend to arrow and spear every outsider as they see them. Some British "visits" where made along 1700´s and 1800´s, with the same results, they even kidnapped a bunch of Sentinelese who rapidly sickened and died without gathering any information about their ways. In the modern era, some anthropology expeditions have tried to make contact with no results, deciding that they don´t want to be bothered. One of the last attempts to make a census, involved an helicopter that was shot with arrows and spears by the Sentinelese. The census couldn´t even estimate a number of people living in the island, there could be from 15 to 400 Sentinelese.
Indian authorities made clear that they will let North Sentinel Island alone, so we could say that is one of the few independent and autonomous primitive cultures in the world.