I vape in my car as well, but when I'm with my boyfriend in the car, especially at night, he doesn't like me using my e-cig. Well, that's because usually in that scenario, we've both been out somewhere drinking and he does not want my
vaping to draw attention to us. Otherwise, I don't see any harm in doing it even if there is a cop looking at you funny. I was standing outside of a club one time waiting for my friends to get out, and puffing on my e-cig. I noticed a few cops looking my way, but they didn't seem to care too much once they saw what it was. The main thing though, is most people know of e-cigs, but probably have not seen any fancy
mods or anything besides a disposable from the gas station. People always say "Wow, I've never seen an e-cig that looks like that", even when I'm just using a Twist with a mini nova.