The War on Drugs was lost before it started, yet it continues on and on wasting taxpayers' money. Part of that waste is directed towards "informing" people why they should do drugs, whether it be tobacco or meth. Millions of dollars go into adverts every year to convince people that they should do drugs, when in fact all they do is annoy both users and nonusers.
I'm not saying there shouldn't be drug education programs. Those can be useful if they are honest, but many are not. The only way to deal with the drug problem is to openly discuss it. Kids and teens need to be treated as equals on the matter. By making drugs seems like a forbidden fruit, it only makes them want it more. Teens are rebellious (at least I was) and if their parents drink, but tell them not to, guess what they're going to do. The same thing goes with drugs.
If you want to prevent your kids from smoking pot or doing even worse things, be honest with them. Tell them about the times you did those sort of things (if you did) or about experiences you've witnessed and what you learned. Let them know that they probably won't die or ruin their life from doing one joint or taking a hit from a bong, but that doing it too much will ruin any possible good experiences. Moderation is the key to teach your kids about anything, why not be honest and tell them the same thing when it comes to mild drugs like pot.
These commercials on TV are really not helping anyone. They either insult the intelligence of the target audience or gross out the person who's just trying to watch a rerun of The Simpsons while they eat their diner. Hell, I almost lit up a cigarette just to rebel against the stupidity of one of the commercials before I realized I just should act my age. If that's my reaction, how do you think teenagers with the same sort of mentality are going to react?