Yes you can, until can't.

eg.
When flying on CX at SYD you are only allowed into the QF Lounges if you have a printed invite (otherwise CX reportedly won't pay QF)
CX will only provide you with an invite if you are flying in a valid class, or have the correct FF number associated with the booking.

Only solution is to accept that at checkin, use the lounge, and then get number changed at gate (but this is relatively fraught with issues)

Reportedly in Amadeus there are differing fields for benefit status and earn status, but they are not easy to access, and as many agents are not trained on it, easy to get it wrong.