I have a friend who works in a hotel/restaurant. They have problems with people who vape because other people think they are smoking and get umpty. At the end of receptions and parties, "umpty" can get nasty.
Even given there is no law against it for what reason would someone want to stick there taunting those who don't like smoking near them ? Where individuals are really trying to give up, they'd be trying to get out of habits not do all they can to continue the same destructive behaviour pattern.
It`s not a legal issue regarding them being taken on an aircraft as there is no law against it. It is a regulation. Most major airlines don`t allow them because if people see someone several rows away puffing on one, they will think it is a real cigarette and it`s OK for them to reach for their fags and light up.
@ Lozzer - I disagree, whilst it's the landlord/airline's discretion whether or not to allow 'vaporising', the e-cigs should not come under the smoking laws, as the laws were designed with the public health and safety in mind namely protecting those who choose not to, from second hand smoke.