It's interesting that there is debate about this. Personally I do check in with most patients now and then about smoking cessation, generally after they raise their smoking as a behavior they are ambivalent about. I might use MI strategies. But if the psychologist positions him/herself as clearly against the behavior, I think it alters the therapeutic relationship in an unproductive way.
From the Ethics Code:
Principle E: Respect for People’s Rights and Dignity
Psychologists respect the dignity and worth of all people, and the rights of individuals to privacy, confidentiality, and self-determination. Psychologists are aware that special safeguards may be necessary to protect the rights and welfare of persons or communities whose vulnerabilities impair au- tonomous decision making. Psychologists are aware of and respect cultural, individual, and role differences, including those based on age, gender, gender identity, race, ethnicity, culture, national origin, religion, sexual orientation, disability, language, and socioeconomic status, and consider these fac- tors when working with members of such groups. Psychologists try to eliminate the effect on their work of biases based on those factors, and they do not knowingly participate in or condone activities of others based upon such prejudices.