We just returned from our cruise, and I can say that we tipped what I hope was generously. When you return home and find that you have to fill your own glasses, cook and serve the food, and clean it all up afterward, their price becomes a small one to pay for being waited on constantly
As far as we could tell, our stateroom host put in at least 14 hours a day, and knowing how little they get paid by
DCL, I wanted him to know his efforts were appreciated. When we had left the room in disarray (its formal night, stuff left around, gotta get to pictures messy), he straightened up and then did turn down so the next night I left him a thank you note and $$.
Every
Disney Cruise, we've had head servers who get involved, so by the last night I really feel they have earned their tip. Plus, my DH has an egg allergy, so we were closely monitored by all servers and met several chefs. So, to me, the guidelines are more than fair, and we always tip above them. When it comes to tipping, remember that many of these people are working on ships miles from home, and sending their pay home to their children that they don't see for 6-8 months at a time.
We tried to bring along enough international phone cards and iTunes gift cards, but I was suprised that 19 counselors worked in the Club, so we just made it without any left over for other crew members. I wish we could have tipped better on the counselors who actually made more of an effort for our son, but in the last minute stress of leaving, I couldn't think of a diplomatic way. We did leave more expensive phone cards for our two concierge reps because we weren't sure what they could accept.
Regarding Palo, we seemed to get the feeling that the tips left covered the server and the other staff, so we left what we would after a nice dinner on land...and even then, we felt cheap. So, I guess we didn't have a great way to answer that either.