We have cruised 4 times with Celebrity and you can take the automatic tipping off your account at reception and pay as you see fit. They are OK about this and you can use envelopes to give individual tips.
May I politely suggest that you use the Find a Question facility at the top of the page and enter "Tips" in the keyword section. There you will find enough answers to satisfy your curiosity and stop me from saying things that only promote dissent in the ranks. .....Neil.