What, and ruin the private playground of these Anthropologists? /sarcasm
Most of these tribes have more contact than the naive anthropologist think, and have learned to avoid strangers because they end up being victims one way or another. And some tribes in the Amazon have been playing the antropologists for years.
No one ever seems to question the ethics of these anthropologists for working with governments to keep these "pet" humans for their private study, watching them die of easily preventable diseases, while refusing to offer help for fear of "contaminating" the population.
Can't violate The Prime Directive, you know.
Just because that star is going to go nova is no excuse to do any more than watch the non-warp capable autochthons be wiped out, rather than contaminate their "primitive" culture.
I don't recall the exact details now, but a few decades ago I read a hilarious article about how anthropologists visited a primitive remote tribe somewhere, and were studying their culture, when the tribe leader asked them if they'd like to hear one of their traditional songs passed down through generations. The anthropologists said, "sure", and turned on their tape recorders as the tribe gathered for the performance. The anthropologists about fell over in surprise when the tribe launched into a four-part harmony version of some old classical music piece from the West. It was something like the "Hallelujah Chorus" from Handel's "Messiah", if I recall correctly.
Apparently a century or so ago, some traveling missionary had passed through and taught it to them.