Or it was more of a buffet thing in my country that had Chinese food (or Asian food at least).
It was back then when I was an early teen and had learned Mandarin from freaking Ni Hao Kai Lan.
And when me and my family were done eating at that place, and we were on the way out, I was bowing and said "xie xie"...
I don't remember there being any Chinese person working there.
I guess that is like saying "gracias" after eating at Taco Bell...