How? It’s only a matter of time before one of the advertisers sneaks in one, it gets transmitted and then gets told not to show that advert again with the device in view. What this does is control the presentation of the device, and ensures that it’s presentation is regulated.
There are strict rules on alcohol advertising, and there were on cigarettes before advertising tobacco products was banned.
Basically, show people having fun, connect somehow with the product, but don’t make direct claims that your life will suddenly become awesome because you‘ve got a little nebuliser* in your mouth.
[*It struck me the other day that there would probably be pretty good as asthma medicine delivery systems. Nebulisers are pretty big things, but they do exactly what e-cigarettes do - turn the drug into a vapour to make it easier to inhale and be absorbed by the lungs.]