I've used mine in restaurants and doing my job. No one has ever confused it with a "crack pipe". Most don't say anything. Some ask what it is and once I explain it are intrigued and ask for more information either for themselves or a friend. I will usually have both the SD and 901 with me. Interestingly, of those who want more information on how to start vaping, the majority actually like the silver, sleek look of the SD and the fact that it doesn't look like a cigarette.
I did have one interesting encounter. I was at a party at a friends house. One guy who I know only casually had been drinking quite a bit and I knew him to be a real anti-smoker. When he came up to me and ask me what I was doing with that "I'm superior" look on his face, I told him I was vaping. He was like, what the he** is that? So I told him it was my personal vaporizer that administered my medication for my condition. He was like "that's cool" and walked away to get another beer. My friends standing around just started laughing. One of my friends ask me what I was going to say my medical condition was? I told him I would have said it was for my "addiction reduction condition" but that I would rather not talk about it in any more detail!