It's not a big deal. People will be curious no matter what you use. You are still sucking on something attached to a metal tube. I've used mine in front of cops and they don't even blink. I carry a 3ml bottle for refills that has a vendor label on it just in case I have to show proof of what I'm doing. Ecigs are mainstream now that stores are carrying them and people know what they are.
I have eGo for backup, but I like vaping all day on one 18650 IMR battery. With the smaller ecigs people know that it's not a cigarette, anyway. They can tell by the lack of smell and the fact that real cigs don't light up with an LED on the end.