I was told that the booking shows gold if you booked when gold. So that is not surprising that they let you in. They have the same info in their system as on the BP (which is not surprising since the BP was just issued). Even if you scan the BP, they will find Gold status. All they could detect is whether you present a fake Internet-printed BP where you change the status printed (that is easy).

Only if the lounge dragon goes into another sytem to check your FB status, would they find out.
Is that info given to me by an AF staff wrong?