There is no legal vaping age. Vape is not smoke. It is illegal to market e-cigs to minors, as well as sell e-cigs and cigarettes to minors BUT a minor cannot be hauled into jail for smoking or vaping. It is 100% legal for a minor to use an e-cig.
As long as the minor does not purchase e-cigs himself then neither he or the seller is breaking any law. It is only illegal to purchase, not use e-cigs for minors and that goes for smoking too.
The idea of underage vaping is we don't want to encourage nicotine addiction however mild it is with the type of nicotine used in e-cigs, to a new generation of addicts.
If a 15 year old smoker is addicted to nicotine via cigarettes and he switches to e-cigs, then he can use them legally, and post videos about e-cigs legally. There is no law against the use or posting videos of e-cigs for minors. ( only the marketing to and selling of)
The fact that you see more minor e-cig videos may reflect the fact that more legal underage smokers are switching to a less harmful alternative.
This is my understanding of the situation. I think it's great that if they Must smoke they use an e-cig instead. Of course we don't encourage new nicotine addiction But teens WILL smoke and get hooked on cigarettes regardless if e-cigs are there as an alternative or not, so I go with the lesser evil.
You Must Not tell these kids they have to stop making e-cig videos ! Kids are impressionable and you could cause the kid to get mad and go back to smoking which WILL kill them.
Ask them to please not introduce the e-cig to kids that are non smokers instead. Do Nothing else. These kids are Not breaking the law.