I know on most cruise lines that staff make a modest amount plus room and board and some additional benefits then the tips. I know
RCCL used to guarantee them so much so if they didn't get a certain level with tips, they would supplement it for a while. If things didn't come around, see you later.
As for this thread, I always find Disney people and tip discussions amusing. It seems many Disney patrons go above and beyond the industry standards for tipping. There are several issues running through this thread. One is whether substandard service should mean a reduced tip compared to the "recommended" amounts. If it's truly substandard, the tip should reflect accordinlgy. Another issue is what is substandard service. Does it mean being overly friendly, magic tricks, jokes, even towel animals or not. Each CM must put together their group of services that fits their abilities and personality. Some will be better than others. The top ones should get more and the bottom ones less. The majority in the middle should likely get the recommended amount of tips.
As for children, each is different. On a cruise, I certainly would tend to give the recommended amount for each person, regardless of age, sometimes more. However, some children are just less or more work than others. For an infant where they had esseentailly nothing to do, I'd agree that a reduced amount is not unreasonable. Or in the case of children that were never at the meals, a reduced amount may be appropriate there as well.
As for the steward that gave the hints in the form of filling out a new form and underlining the children amounts, I'm quite certain I would have left him less because of that behavior rather than more. Had he been a poor performer otherwise, I likely would have left him nothing and been tempted to go back to college days and left him a small tip under glass.