My theory is that Harbaugh got a warning but, unlike Bryant, didn't back down. Also, my theory is that Harbaugh "threw caution to the wind" because at that point it was already first down and the penalty would only give New England 5 yards. Yeah, I know yardage becomes tougher down in the red zone but 5 yards in the red zone when it is already 1st down isn't as painful as if, suppose, the exact same thing happened on 3rd and 20 to set up 4th and 6. If it was 4th and 6 Harbaugh would have checked himself since a personal foul is much more damaging at that point.