Well, if Bruce says the tips are pooled and always have been, I'm sure it is true. And I'm glad to hear that the service crew on your Princess cruise was good. We have cruised many lines, both "budget" and "luxury" and have always found the service to be better than anywhere we could go on land. That is why I advocate "going with the program" on tipping, whatever it may be. Envelopes with "suggested amount? Do it. Auto tipping? Do it. Tips included in fare (my favorite) You'll do it as you have no choice!
Bruce may be surprised to learn that although I am sensitive to "nickel and diming" on cruises, I don't consider tipping to be such. In the US, we tip for good service, by tradition. For the high quality of service we've had on all levels of cruise lines, it would be criminal not to tip. We had some friends who went with us on a line with "tip envelopes on the last night." They skipped out on the last hight and stiffed all their service crew. They are our friends no longer, and we'd certainly never cruise with them.