I sincerely applaud parents, grandparents, aunts, uncles, sisters, brothers, etc. who encourage the young people in their lives to cultivate healthy habits. "Just say no" and all that stuff? Yes, do all you can to convince them to eschew illegal drugs, smoking, drinking, and so forth.
Just... Do you really think it's necessary to make and wear an anti-smoking sweater?
Unless you travel around the country talking to kids about the evils of smoking, I can't imagine many occasions that call for a "NO TO SMOKING!"-themed sweater... but maybe I'm just not going to the right places.