I'm a black guy. Yes, I would say happens alot here especially at some local places. Where I live, I have a white friend who hails from the UK. He always visit me with his two daughters because where he lives the locals there for some unknown reason always uses Thai derogatory slurs on him. It even get into some point where his wife brother knocks his door for money to buy lao-kaoh. I think it's always better to Keep a cool when engages with them as most of them lacks Social etiquettes.