I think it's more of a cultural/expectation thing. It's been done as a courtesy for them for so many years, that it has become expected. I print pairings for them simply because I'm printing one out for myself and it's just as easy to hit the "5" key as it is the "1" key. No biggy. I usually sign them in but again this is something that takes all of 2 minutes. Most say thanks but not all. Being nice to the FA's does pay off most of the time. When you are, they seem to check on you more often and offer us better service in the air. I would say that some pilots have come to "expect" certain things from the FA's while working that is not in the FA's job description... I've just found that if your nice to them, they are usually nice to you. Makes for an easier trip. All for the cost of 2-3 extra minutes of "work" on my part...