I vape and my kids see it. (Teens)
I used to smoke. They saw me smoking when I went outside. It wasn't easy to hide as they got older. We have chats about it and I think mostly they are relieved it's not fags. I don't vape constantly, it's occasional perhaps in the kitchen when they aren't in the room, or outside the car before I drive etc.
I do not vape around anyone else's children because I am aware that not everyone likes it or approves. I try to do it outside or alone but I am also conscious that i don't want to make it an elicit secret, neither something habitual so very hard balance
I am trying to be rational here, with teens I mean I don't think never seeing adults drinking or smoking would mean it's less likely they do or don't do it - teen DD's tell me vaping is RIFE at secondary school, even weed flavours. Or real weed 
So I'm quite glad we have more of an open dialogue where we can talk about it, so I have told them that it's still a risk - no one knows the long term effects of vaping and I would like to give up the vaping.
The charging of the bloody thing seems to put mine off 