I fly a huge amount on United, and I've only once ever really noticed an NRSA on board. The person was sitting next to me, and we chatted a bit. My sense is that being a flight attendant or pilot is a very demanding tough job with not great cash pay for what it is, and NRSA travel is part of their compensation. I see no reason why they should have to behave like stoics while traveling, although I also do not condone rudeness to passengers.