While I agree with Vocalek's reasoning, as a parent, I would be upset if I found out that my child was buying tobacco smokes or ecigs. But I also don't think children should have access to red bull and I certainly have had to go round and round with a daycare provider who thought it was time for my 2 year old to be on ADD meds.
That being said though, as a parent, if I did find out my child was smoking tobacco, I would like to have the option to help her determine a better alternative to her nicotine needs. This whole "contributing to a minor" thing should not always apply.
Just like I plan on arming her with valid information on how to keep her safe from the downside of sex, I will do the same with everything else. As a parent it is my right to purchase, for my child, what I think is best for her, whether that is the birth control pill, condoms, an abortion, OR an ecig.
This, unfortunately, is one of the biggest things our society has lost. There is no doubt there are bad parents. But there are also parents who take seriously turning children into responsible, free thinking adults.