Last month I flew two stand-bys for earlier flights. My the first flight was originally booked in K and when I cleared I was issued a BP with a K. When I made it to DFW and checked my status for the next flight the AC agent gave me a stand-by BP with a fare code of Y even though it was orginally booked in V. When i cleared stand-by at the gate I got a real BP again with Y. A few days later the flight posted to my account and I got 1.5 EQP for the second flight. I didn't pay for Y so, I guess it can happen.