Originally Posted by
LH/LX
Many people are lucky enough that they book on heavy booked flights on certain routes and it happend that they were just promoted to the next tier. When they go to the airport they get upgraded becuase of the overbooking of the flight and they assume because of their new status

Or.. the check-in agent tells you are being upgraded for renewing / hitting 500k or 1m miles. have had it happen to me several times. in most cases j did not seem full when i was upgraded to f.