As an African female living in the US, yeah, I have. Pretty recently, actually. I went to CVS to buy some tums and a soda, and this cash register guy tells me, "Get out of our country, you fucking n-word!" And refuses to let me pay for it. Well, what're you gonna do? I just went to the other guy and explained what happened. He was extremely sorry for his co-worker's words, said he'd have a talk and inform their boss, and let me pay with him. The guy that yelled at me stared me down out the way.
That wasn't a good day for me.