I've shared this story before, and since it is relevant to this thread, it's worth repeating.
My daughter just turned 18. She doesn't smoke, but her 19 year old brother and several of her friends do.
She always had taken an active interest in my quitting smoking using electronic cigarette devices. I did allow her to "sample" my new flavors when I got them, and we'd compare our like or dislikes.
She recently asked me for her own mod for her birthday. She wanted to use zero-nicotine juices but still be able to enjoy the flavors. I had previously been against non-smokers taking up vaping, but that was because of the nicotine issue. Why start a habit to a known addictive substance when you have no previous addiction to it?
This situation was different. Should I be pro-active and encourage her to vape, using the no-nicotine juices, in the hope that she would not take up cigarette smoking. My rationale was yes; far better to vape no nicotine than risk starting up smoking.
I purchased her a pink BB mod with 3 batteries, a charger, and a couple of Vivi Nova tanks. I got her 3 bottles of zero-nicotine e-liquids in the flavors she wanted.
Her friends had tried my mods and liked them, saying that this was a better alternative than smoking. A few of them went online and purchased their own eGo kits, and are now vaping instead of smoking. Seems like a WIN - WIN to me.
Now, others may disagree with what I did. But she is now 18 and could have purchased a setup on her own. At least I know what would be a good fit for her.
In no way do I approve of under 18 year olds vaping, nicotine or not. But once they reach adulthood, it is their decision to make.