As a PL resident, my M&M card has the LOT logo on it, same goes for my on-line account, which is also LOT-branded.

That aside and as for the AF/KL thingy, I've never really paid any attention to it but I've just noticed a mix of both AF and KL on a few recent boarding passes (for the records, I had originally registered through KL in the UK and remember the option to choose either AF or KL during on-line check-in, I therefore doubt there's anything which would suggest a profiling exercise in relation to most frequent airline, country of residence and the likes). With other Sky Team airlines (e.g. AZ), selecting Flying Blue during on-line check-in will automatically default to AF.

G