Isn't funny how covert you have to be when you are sketching people?
"I'm not hiding a sketch book on my lap!"
"No, this isn't a sketch of the back of some guy's head, really. I'm just sketching ...a possible landscape plan for my yard"
And then if you do get caught...
"Yeah, it's just something I do..." "Yeah, working for Disney would be...great" "No, actually I illustrate..." "illustrate-you know the drawings in magazines and children's book, yeah, that's illustration." "Actually, um, I don't really have the time to, uh, illustrate your daughter's children's book." "$200? wow, yeah, that's tempting...but I'm really kinda swamped...."
ah, waiting rooms.