not sure, i remember something from ft, paging timt.... 
Is this from the days when they used to let your account go negative, as long as you earned it back by the end of the year? In those days, it was part of the T&C's to agree to pay for a negative balance after a year. Right now, no such provision exists, AFAIK.
Are you referring to the FT thread about the points amex accidentally deposited into some accounts December time, and what would happen if you took them and ran? There were no real pertinent data points in that thread, IIRC.
