That’s what my mother said too (her grandmother was full-blood Cherokee). Until more recent years, Indian heritage was not something people were proud of, at least openly.
I knew a lot of Cherokees that called themselves Black Dutch. Truth is anyone without a roll number is better off saying nothing, no casino money for them. There were five civilized tribes in Oklahoma along with a couple dozen uncivilized I guess, why do we not have people claiming to be Quapaw? Just a guess here but it might have something to do with money.