you chinese?

every other month, someone asks me "you chinese?" or "you korean?". like tonight, i was buying beer. the old chinese man asks me "you chinese?". i said no, i'm japanese. he said oh, and that was that, i handed him my credit card. but after the transaction, i started to think. what if i lied and said yes, i'm chinese.

  if i lie, i assume that there is no way he can verify

scenario a: i tell him i'm japanese, i pay for my beer, move on

scenario b: i lie and tell him i'm chinese, (assume there is no way he can verify), and maybe make a new friend? get a discount? get future discounts?

am i missing something? there's no downside. only upside