Are you supposed to tip? I don't do a lot of INTL travels; even when I do, I am usually traveling in coach anyway, or on *A airport w/o fancy dining lounges, or non *A, sometimes I don't even visit lounges despite being eligible. I just don't care too much about it, and usually arrive to the airport very close to departure.
I think I have been to PL twice in my lifetime (EWR and SFO on separate trips) and had sit down dining once, and did not leave any tips.