If only there were a completely stealth vapor. The best on the market is only relatively stealthy (without fussing with breath control). You could vape anywhere with absolutely zero interference from other people. I doubt there would be much, if any, public or professional outcry at what we're doing if there was no visible signal.
It's too bad we place so much stock in the vapor production of our devices (me included). On some occasions (planes, offices, supermarkets), I would be perfectly happy to just get my nicotine fix and forego the 'clouds of vapor'. I think the company that comes up with this device/juice solution will make some money.