In some places in Brazil perhaps it was the way it used to be in Cuba? I've known a few "white" Cubans quite well, children and grandchildren of people who fled Castro's Cuba.
They never suspected that they had any non-European ancestry; they only found out when they did one of the retail ancestry tests.
In all of the ones I knew, most had a few percent SSA, and a few also had a few percent Amerindian, and carried Amerindian mtDna. The latter was the biggerr shock as the history books had said that the "natives" were exterminated. If I remember correctly, the Amerindian showed up in the eastern part of the island.
The totals were never more than around 5-7%, and it certainly wasn't visible.
In the case of Cuba, these people, who were indeed the "elite", all fled when their properties were confiscated. One of them returned for a visit, to the anger of his family and friends, and said from what he could see there were no "white" Cubans left. That entire part of Cuban history is gone.
Many of the people who remain do carry European ancestry, of course.
I suppose another example is the Afrikaners. The first settlers were men; they took mates from among the locals or the slaves, but some of the children of those unions then only admixed with full Europeans, and so the other ancestry was diluted.
Coincidentally, there was a clip on my youtube feed yesterday about Sally Hemings, the slave "concubine" of President Thomas Jefferson. Historians and his white descendants have always denied it, but recent dna testing is pretty conclusive.
This poor mulatto or quadroon girl gave birth to six or seven children, starting when she was just sixteen years old. Even more appalling, she was the half sister of his deceased wife and much older. He never treated them in a "fatherly" way, but she, and they, received "special treatment", and when they were 21, two of the children, a boy and a girl, were "allowed" and actually aided by him in "running away". They "passed" into the white community and their descendants are unknown.
Two boys, Eston and Madison, remained with their mother, whom he never freed. She was freed after his death by Jefferson's daughter. He did free the two boys in his will. Madison chose to remain in the "colored" community and he has African American descendants today. Eston took the Jefferson name and claimed Thomas Jefferson as his father. He married another mostly white woman, and his descendants were part of the white community. The connection was a family legend but dna testing has proved the males carry Thomas Jefferson's specific yDna.
There are no pictures of Sally Hemings or of Eston Hemings Jefferson, Thomas Jefferson's son, but this is his son Beverly.
This is another of Eston's sons, John Wayles Jefferson, who became a rich and successful cotton broker.
Clearly, 5% SSA doesn't "show".
The whole thing disgusts me. I think he freed them but not her because be believed (the statement is found among his account books) that if a slave is an octoroon, or only one-eighth African, they perhaps might be considered "white" enough to be freed. I think he said something like one sixteenth or one thirty-secondth is "better". Don't quote me but it was something horrible like that.
I know we shouldn't judge the people of the past by the standards of today, but by that time some people were already indeed appalled by such callous and immoral behavior, among them President John Adams and his wife Abigail, who fell out with Jefferson when they found out and never really spoke again.