What about the problem that lots of people are of mixed race in this country, and not all of them look "African?" How is a person going to prove he or she has slave ancestors? That's a lot of expensive DNA testing.
Not even by DNA testing can you prove that your ancestors were here during slavery. I suppose if a particular family has maintained rigorous family records, that'd help but I can't imagine how such a task would be undertaken. Imagine the MONEY it would cost first of all. Now that I'm methodically thinking about it, it's even more of a bad idea than I thought it was previously *LOL*