I was on NW547 BOS-MSP Tuesday night, riding in the back with a bunch of other plats. I tried using a CO Currency voucher, and the FA was not at all happy. She raised the point (numerous times) that all the FAs on the flight were 30+ year FAs, that combined they had >120 years experience, and none of them had ever seen a CO voucher, and didn't think it should be accepted. I raised the point that it was in the manual (the FA was then confused as to which manual, I said I assumed it was the service manual), and she told me that she didn't have time to look it up, and none of them carried service manuals anyway with them since they were large and they were only required to carry the safety manual. She finally went and asked the lead FA, who also was not happy, but said "I'll accept it" as if I should be grateful. (I wanted a Baileys + Decaf).

Then five minutes later, another FA comes along with a 2nd cup of decaf (guess there was some confusion), and I said "Thank you, but your colleague already gave me one". She replied that she brewed a whole pot, and asked if I wanted it anyways - I said sure, and asked if she would take another continental currency voucher for another baileys. She said don't bother, and just grabbed one from F.

Overall, lessons learned:
1. FAs don't always know the policy, don't always feel like looking it up, and don't necessarily even have a copy of the manual on the flight.
2. They are not thrilled about seeing something for the first time.
3. If you stay positive and happy, it can work out to your advantage. (2nd drink was free.)