We sailed only once on Celebrity and our cabin was in between two cabins full of chain smokers - even the hall was blue with smoke. they would prop their doors open to clear the smoke out of their room = and of course, right under the door into our room. We couldn't spend any time there because our eyes burned and watered and we had sore throats. The occupants of the other 2 rooms gave the same reasoning - we paid the same for our cabin and we are entitled to smoke in there and so we will. There was an open covered area 50 steps away where they could have done some of their smoking. Even the steward was upset by all the smoke.
Where were our rights to breathe clean air and not have burning eyes and sore throats?
On the lounge deck smoking was allowed all down the port side but if you sat on the other side the smoke drifted over and we were never able to sit very long before having burning eyes etc. again.
We have never sailed with Celebrity since and are happy with HAL's smoking policy and have never been bothered with heavy smoke - except for the casino - on any of our cruises with them. We just stay out of the casino - but we couldn't stay out of our cabin on Celebrity.