Mike, where does it say that? Given that the additional charge for the speciality restaurant has risen over the years, at what point did they decide an additional tip was needed? And given that Celebrity (a) add 15% to all bills, (b) tell you when and what to tip and (c) are now collecting gratuities direct to seapass accounts, why don't they just add it to the speciality bill there and then? It seems strange to me that this is the only tip they aren't up-front about. They certainly tell you how much to tip in the casual dining bistro, where they now...add it to your seapass account!
As a Brit, I think it's important that Celebrity make these issues completely clear. Britons don't have such a strong tipping culture as Americans (talking to US cruisers aboard Galaxy last November, they were staggered when I told them it is not expected that you tip the bar staff in British pubs, for example) and it seems to me that Celebrity are quite clear on these issues - except for the speciality restaurant, it seems (if you are right).