Sketching in public?

I'd love to hear your ideas, suggestions, and experiences. Please share!

Here are some people-sketches done with different approaches...all worked for me!

Ask permission!  This young man was in my pottery class, and I loved his dreds, so I asked if I could sketch him.  FUN.

Airport people are always interesting, and make great subjects.  Usually, they're preoccupied with their own plans, waiting, reading, or snoozing, like this fellow.  I usually sketch quickly, not staring in any one direction for long.  Lots of glancing...and if I'm caught, I smile sweetly.  So far that's worked!

Sketch from a distance...these were quick gesture sketches of my neighbor across the street.  He didn't even realize I was practicing!

When sketching in public, you may be sketching the landscape or a building, or like these examples, you may be sketching your fellow passengers or diners in a local cafe'.  Different approaches to different subjects...

Fred Crowley draws in a Panera's, and does a lot from memory.  Roz Stendahl sketches among the crowds at the State Fair, Liz Steel does wonderful travel sketches, Laura Frankstone works in cafes and on cruises, Alissa Duke sketches in museums and botanical gardens, all of these with people around. 

In fact, many of our correspondents have found ways to work in public.  So how do YOU handle it??