My husband's mother swore she was "half" indian. They were from Copia County, MS via the Carolinas. The doctor diagnosed my husband with a health condition almost exclusive to African descendants. Since he is white, we started tracing his lineage and found this "indian" ancestor on the SC slave tax rolls prior to the Revolution. My husband had the DNA test which confirmed he was likely of black and not Indian descent. If you research early Carolina history and the migrations into GA, AL, MS, and back to Tennessee and Kentucky you will find evidence to support these false "Indian" rumors.
I spent 30 years tracing my "Indian blood", because my great-grandfather insisted he was Indian. I traced his family and discovered he had absolutely not a drop of Indian blood.
I live in the Midwest, so I know there are a lot of undocumented natives. So, I don't want to discredit anyone who is or might be. But, there were also several reasons to claim to be natives, when you weren't.