In my experience, I get more heat from uninformed spectators than cops. I live around Burbank, CA, and as anyone who has been to downtown Burbank can tell you, it is illegal to smoke in public places. That being said, I started vaping while I was walking down the street on my way to grab a cup of coffee. I passed by this couple who whispered to each other about about how I was breaking the law by smoking. I let it go knowing I was completely within my rights and the right side of the law. Later that day, I was vaping outside a bar around the same area. Some cops pulled over to the side of the road, looked at me for a second and got out of their squad car, then they walked to the other side of the plaza. All this happened while I was vaping. Since then, I don't mind vaping in public even if their is a smoking ban. I just mind the bad looks I get from people who don't know what I'm doing and "assume" I'm doing something illegal.
As far as getting pulled over is concerned, I have not been pulled over for vaping. I have stoped at a stoplight with cops next to my car, but nothing ever happens. I go my way and they go theirs.
The few times I've hit my ecig while riding the subway, usually because I'm on a train that has been delayed, people literally get out of their seats and move away from me as if i'm dangerous. This is a very conservative area lifestyle-wise probably doesn't help that I have a lot of tattoos.