The best I understand is that the Piapot adoption is similar to other adoptions in that bloodlines aren’t necessarily an important part of the process. So from that point of view BSM can legally enjoy the same benefits as every other First Nations member. From the included link:
Ntawnis Piapot, speaking for the family, says the bombshell claim that Sainte-Marie has no Indigenous blood has no bearing on her belonging to the Cree family.
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Piapot says Sainte-Marie connected with the Piapot First Nation after she met her grandfather at a powwow in Ontario.
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“The adoption process, it took years — it took days and months and years of getting to know each other and trusting each other and going to ceremony and getting her Indian name (from my mushum) to finally look at her and be like, I acknowledge you as my daughter, you’re officially part of our family
.”
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As well, the United Nations Declaration on the Rights of Indigenous People states, in Article 3, that “Indigenous peoples have the right to self-determination.” Self-determination means “the sovereign right and power of the Indigenous group to decide who belongs to them, without external interference.”
Indigenous icon Buffy Sainte-Marie's identity was brought into question by a CBC investigation, her Piapot family says the accusations are "ignorant, colonial -- and racist."
globalnews.ca
There’s much more at the link. The information regarding BSM’s birth certificate and biological parents weren’t known at the time the now deceased parents chose to adopt her. Currently the tribe has decided to stand firm by their decision so legally anyway it’s a done deal.
I personally have a problem with the moral implications since it appears that BSM at some point learned the truth but instead of explaining in the same way the tribe did she chose to continue the fabricated history.
By continuing a false narrative BSM ignored the impact on other indigenous people. Make no mistake she benefited greatly by letting the public believe she was a victim of the Scoops.
Could her music have held up on its own merit if she had been honest? We’ll never know. MOO