In this Thai Health advertisement, two small children approach random smoking adults on the street and ask them for a light. Unsurprisingly, those they ask attempt to educate the kids on the dangerous of smoking and magically, the hypocrisy is brought to light. There's a nice simplicity to the ad, but I can't help but feel that, like many smoking ads, it assumes those who do smoke are oblivious to the risks.
It's definitely clever in its approach, but it should be pointed out that most adults who smoke do already knowing the risks. On the other hand, it can be argued that a young child might not, so I'm not surprised by the mini-lectures provided by the people in the video.
I'm not a smoker, so I can't comment on the persuasiveness of the video. What I can say is that, while it's clever, I don't see it being more or less effective than the super-gross-out-cancer shock ads we see in Australia.