I reckon it is the employers right, but I have previously had no issues chilling out with smokers outside whilst vaping, or stealthing it in hidden corners.
Sure, vaping is a lot less poisonous than smoking, yadayada, but unless you are on zero nic, you are still satiating a craving for nicotine, and most emploers won't let alcoholics drinks shots, or smackheads jack up at their work stations. Okay, get the union on that, Carry On At Your Convenience.
But I feel the same way towards the rights of venues, if it isn't clear that a pub is a vaping pub, I'll ask behind the bar.
People working in or running places have enough guff to deal with without having to deal with the irate customers or employees that you get everywhere that'll piss on everybody elses fun, so don't be like them, don't be mememe, have an ounce of self-control too, if you can't survive a few hours without a fix, get therapy, or patches
This may seem arsey, maybe because I'm applying my own values in relation to this predicament to print, but really it is just an honest opinion. And I would love a workplace that allowed me to jack up and vape at my station
What I am outraged about though is not being allowed to masturbate in churches!