That would be Elliott Erwitt, a Magnum photographer who has become best known for his quirky and often funny photographs of dogs. I purchased an excellent book of Erwitt's work called Snaps while i was in Norfolk this year, which i thoroughly enjoyed looking through and regard as one of the best photography books you can buy. Not many photographers manage to combine thoughtful humour and documentary image making, but Erwitt does it with style.
I came across the above photograph, one weekend in Stoke on Trent as i was going into town. It's the only photograph that really comes to mind if I'm asked about carrying a camera at all times. This scene, when i saw it, instantly made me think of Elliott Erwitt and fortunately i had my camera with me. It's not as clever as his images tend to be, but it does have at least some humour in it.
Does it pay to carry a camera at all times? Sometimes it does.