I have to concur with the majority, and I'm reminded of a statement made by
Sir Ken Robinson:
"A three year old is not half a six year old."
Children are not lesser people, they're simply
young people. More importantly, they're the people we've charged ourselves with training to become productive members of our society and that duty is of paramount importance. I believe the only way to do that, is to help them disseminate fact from fiction, and teach them how to reason and think responsibly for themselves.
The best way to ensure that children will experiment (possibly dangerously) with something that should be taboo for them is to disparage or vilify it without explaining its consequences.
Even though I avoided smoking in front of my children (now 12 and 8 years of age) due to the harm it could do them, they knew that I did it. Obviously, their olfactory senses knew something was awry and lying to them would have served no purpose, but instead would likely have given them the impression that I was guarding a secretly wonderful thing that I didn't wish to share.
I vape in front of them with absolutely no guilt about it. For that matter, now that I've turned my father (a 45+ year smoker) into an enthusiastic vaper as well, my children consider me a hero of sorts. Not only do they see this as a gift to grandpa, they consider it a gift to them...a gift of more time with Daddy and Grandpa. My mother's pretty happy with me too.