>Chinese woman comes into store to buy wine
>looks about 21, so we have to ID her
>"S-sorry, I no good English"
>I interject and ask to see her ID in Chinese
>facing disciplinary action for racism as I 'shouldn't have jut assumed she was Chinese'
>Couldn't just say that you recognized her accent.
This. If you speak Chinese then you obviously have an interest in china and have interacted with Chinese people before. I speak conversational Japanese and could recognize a Japanese accent quite easily.