The current behavior probably comes out of the RFC822 world, where when seeing a line that doesn't look like a header the error recovery is to treat that line as the beginning of the body (ie: assume the blank line is missing).

Is there in fact any guidance on what the optimal error recovery strategy is for http?  I've actually considered trying to make the error recovery in email smarter, by seeing if the *next* line looks like a header before making the decision.