Originally Posted by irishguy28

For several months last year, I would access KLM lounges with my Alitalia status card, while travelling with my Flying Blue number in the booking.

The lounge agents would frequently begin to overwrite the number, but I explained what I was doing - rebuilding my status in Flying Blue and "coming home" from Alitalia - and it was never a problem.

If you explain, briefly but in clear detail, what you are doing, it should not be a problem. I never failed to gain access (even at some third party lounges in DUB and HAM, which surprised me) and my miles never went astray.