I really doubt they try to determine the immigration intentions of strangers they encounter.

From what I hear, they kill any outsider within spear range.

That isn't entirely true. There were contacts between them and Indians from the government on more than one occasion. These were cautious but peaceful. There are photographs of these online.

So they are not, strictly speaking, "uncontacted" in the sense that they haven't had non-violent interactions with outsiders.

I looked this up, and you're right!

Thanks for teaching me something new. That doesn't happen every day!

It is the way it is reported. There are very few truly uncontacted tribes. I'm not referring to aircraft and distant sightings. Some have had negative interactions with loggers, miners and fishermen etc, but the North Sentinelese have had some positive interactions with the outside world.

Maybe we all are the North Sentinel Island of the Milky Way. Now there's a thought.