Suggestion from Frances Schultz, in the form of an imaginary encounter with Weegee:
"Excuse me, sir, I believe you are about to be shot. Would you mind falling to the right so it won't be a shallow photograph?"
Stieglitz, The Steerage. Another unposed street picture.
As for HCB's 'fleeting relationships', what evidence is there of this? I never met him myself but I have friends who did. One (Frank Drake) described his style as 'shooting before anyone had realized he even had a camera in his hand'.
Finally, Les, you may have seen my AP piece in which I suggested a national contest for street photography, every month, with modest prizes paid for out of lottery money. After the London bombings, suddenly the police were asking for pictures -- when the rest of the time they were trying to stop photographers taking photographs.