More likely along the lines of other people not wanting to breathe your second-hand nicotine / whatever the hell else might be in this vapor, because the jury's still out on their safety.
[1]-http://informahealthcare.com/doi/abs/10.3109/08958378.2012.7...
This study was unable to detect any environmental contamination from nicotine: http://clearstream.flavourart.it/site/wp-content/uploads/201...
"Among all, the most interesting aspects we observed was that nicotine was not detected in air during the e-smoking session, although liquids used for experiments contained it. On the other hand, 34µg/m^3 of nicotine were found during the smoking session."
I remember another study I'm having trouble finding that was able to detect some nicotine in the exhaled vapor using a different method (capturing exhaled vapor in a glass chamber), but at an extremely low concentration. Nothing I've found leads me to believe secondhand nicotine exposure from e-cigarettes is a significant hazard.