Suppose I was asked this negative question:
You are not a student, are you?
and I'm not a student.
Years ago I read in a book that in American English the answer would be
No, I'm not a student
But in British English, the answer would be
Yes, I'm not a student
Apparently this allowed the character to identify someone's allegiance not unlike the way you count with your fingers. But is this true? Because I can't seem to find anything that supports this, only the usual "4 way system yes no yea nay"