You're dead right there, Lawyerboy.
I believe that the obligation is only moral (as in the Hippocratic Oath) rather than legal. The story just struck a chord as I remember reading about it in the papers; as I said, I couldn't exactly remember when.
From your reply it looks as though Doctors would be safe from litigation as long as they had acted professionally - and no doctor would ever insist on payment before treating a patient, except perhaps Dr. Nick Riviera, eh??