I’m happy to say I don’t recall ever seeing one in the SF Bay Area, though I do remember when housing discrimination was outlawed and the furor over whether you had a right to decide to whom you would rent property.

And I remember my elementary school being desegregated (defacto segregation, not de jure) by busing in kids from the majority black community and putting 3 black children in each class. I don’t believe any white kids were bussed into the neighboring black community…