i rarely go out, and when I do i rather do everything else but draw.
but the times i've drawn in public, i loved it. It's like catching the figure while is moving, and when they ask me for a drawing i feel like a pretty girl is asking me to make out.
I don't mind if they want to look at my sketchbook, and everytime they point at the nudes, or weird stuff I come up with something like: Broh/sis, it's art, you gotta practice as you study, you gotta let your hand flow with your mind, as the weirder could be the situation, more you'll improve!
I think the people's reaction will rely on your actitude and self confidence.