All agree that the reduction of teen smoking is the goal, and a worthwhile goal. But when those that are engaging in the behaviour trying to be reduced face no punishment or consequences for engaging in the behaviour most attempts will be futile.
While another long stretch analogy, say the goal was to reduce teen speeding. Who should be ticketed and punished, the speeding teen, or the guy that sold them the car?
That's a different situtation, speeding is illegal for everyone. A better analogy would be teens driving before they are old enough to get a license.
Although driving without a license is also illegal, I must add. The point is should you punish someone for driving if they are too young to understand that they shouldn't be driving.