The resturaunt had a racial segregation policy, banning non-white people from eating there.
In 1955, the Thirteenth Doctor, Graham O'Brien, Yasmin Khan and Ryan Sinclair sat inside, discussing Rosa Parks. However, moments after sitting down, people stopped talking and stared at them. A waitress came over and told them they would not be served, due to Ryan being black and Yasmin for being brown (or "Mexican", in her terms), and so told them to leave. Due to their hatred of racism, the group left in disgust. (TV: Rosa)