So I was back in San Francisco on business a few weeks ago and headed to the Montgomery Street BART station to catch a train to take me away from the grime and madness of The City to the relatively more palatable grime and madness of the East Bay. Which is when I spotted them -- a couple of young men standing in front of the train station staircase. They were waving sings and carrying on and generally making a nuisance of themselves by trying to stand in front of rapidly fleeing passersby. They also were singing -- at the...