So back in September, I wrote about e-cigarettes. Turns out, I'm not much of a fan. As I noted back then, the FDA attempted to ban them in 2009, but the ban was overturned due to lack of evidence, and so it is that you currently have ads about how "we're all adults here" and some rather indignant e-cigarette smokers adamant about how it's just water vapor, and things along those lines.
The thing is, when you call something an e-cigarette, you're practically inviting everyone within hearing range to pass whatever rules they need to pass to treat it like a regular cigarette. Even if the FDA couldn't get a ban enacted, that doesn't stop anyone else with smoking bans from telling e-cigarette smokers, 'it's close enough, now put that thing out'. For example, New York City, Chicago, a whole slew of college campuses, or the entire European Union, which are all in the process of putting legislation in place making cigarettes and e-cigarettes legally equivalent, or which have already done so. The FDA may have to go get more data, but they've seen enough.