answer: #Person1# sits beside #Person2# and asks if #Person2# minds #Person1# smoking. #Person2# does, besides the place is a no-smoker.
documents: #Person1#: Excuse me. Is anyone sitting here?
  #Person2#: No, nobody.
  #Person1#: You don't mind if I smoke, do you?
  #Person2#: Well, to be frank, yes, I do.
  #Person1#: Oh, I'm sorry. But this isn't a no-smoker, is it? I mean would you mind if I smoke here?
  #Person2#: Actually it is. Perhaps you haven't noticed the sign.
  #Person1#: Sign? What's sign?
  #Person2#: There, on the window.
  #Person1#: Oh, sorry. I didn't notice it. Sorry.
  #Person2#: That's all right.