We just finished our first cruise aboard the Millennium and I too was "concerned" with the proper tipping policy. I opted to leave my tip on the seapass charge card, it could be done for the "suggested amount" with the option of adding an additional tip to anyone you desired, but you could not tip below the "suggested". I at first had resisted the whole tipping thing, like others felt the waiters etc should be doing the job they were paid to do....then I experienced what a FANTASTIC service I was provided. When one considered the tab for a meal of this sort at a fine land based eatery, the suggested $4.00 per person is quickly recognized as well less than HALF what an expected tip would be. And the staff more than deserves the gratuity.
I too wanted to make sure "my" waiter etc. knew that I indeed had "taken care of them" on my SeaPass charge...so I asked him about how it operated....he assured me they were credited for the tips before we left the ship...sure enough on Saturday night while others were trying to descreetly handle their envelopes...he thanked me and assured me that he had "recieved" his tip. I would encouraged others to think about the fact that this level of dining "onshore" would result in at the minimum a $50 per plate charge...the level of professionalism in their service would indicate that the $4.00 suggested tip to be well below what one would expect to offer as a gratuity. And hey, on the off chance your waiter just isn't cutting it...you can ask to be re seated, or certainly opt to NOT tip accordingly.