Originally Posted by
IAH-OIL-TRASH
Even that might be gamed. Someone might want their UA FFN on a itinerary, say MSY-IAH-FRA w/ IAH-FRA operated by LH to get lounge access at MSY and then swap to M&M at IAH to get LH credit (for whatever reason)
You shouldn't need your FF# on the reservation for lounge access. *A rules specifically allow access by showing a BP and a *G card.