The articles I read mentioned that they particularly revere their elders, and they are terrified of losing them due to a virus that they've heard can be particularly deadly to older people.
I also recall my interactions with the Havasupai tribe in Arizona (Havasu Falls is on their property) and found them remarkably set in their ways. They had absolutely no interest in my suggestions of how they could "improve" their revenues and tourist industry, explaining that they were quite content to continue doing what they've always been doing, with no interest in increasing their interactions with us (kinda like chassidim?
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I remember schmoozing with the (white) woman at the USPS branch there, who told me that it's the most maddening job she's ever had, and she was desperately trying to get reassigned before she lost her mind. So it doesn't shock me that the Blackfeet's reaction to all this would be to slam the door shut in the interest of self-preservation.
What I'll be watching for is the response of the park superintendent, who may be under pressure from a large number of local business owners whose entire annual revenue will go up in smoke if nothing is done.