I can actually believe this.
I tried it out as well with similar results.
Went to a restaurant in camps bay, waited 15 min for a table while i could see tables available, continually advised that the tables are reserved. Eventually went in not aware of any discrimination, but then watched the door with people coming in, who is waiting and who is getting tables. I decided to test my theories and I was right. The doorman actually told me to go to the Indian restaurant next door!! I stood infront of him, called the owner in JHB, got the door man fired on the spot. (I know people)
The next day I went to the Indian restaurant next door, but also to see if the door man at previous restaurant was still there, he was not. People at the Indian restaurant confirmed my theory, they actually like it because it brings more patrons to their place.
Unfortunately im very rude to white service staff in CT, it works better though. Dont say hello, just say "Hey! table for 6" unbelievable how well it works.
We much more fortunate here in good ol JHB.