I'm sure Celebrity can adjust or eliminate the automatically added tips if a passenger wants to do that. I would hope that if someone receives such poor service that they don't want to tip, that they have brought it to the Purser's attention long before it's time to tip.
Thanks Sandy! That should would relieve poormom's concern. I was pretty sure they would be adjustable, but wasn't certain. I was at the purser's desk on debarkation morning on my last cruise (Carnival), and this group was there removing all there tips just before they walked off the ship!
I almost made a smart remark to them, but refrained. I don't like doing things like that but I came close.