I've got a question on this:
Illegal Participation is a spot foul, enforced using the all but one principle.
Illegal Participation does not occur until the substitute player actually participates.
Play 1: A is 1st and 10 on the B15. Player B1 goes on the field at the B40, the ball is snapped. Player B1 is running to the B35, then the QB scrambles around to that side of the field, and B1 instead of continuing towards the B15, blindsides the QB at the B30.
Is the foul for illegal participation enforced from the B30/B32/B40 (wherever B1 decided to 'participate')?
Play 2: A is 1st and 10 on the B15. Player B1 goes on the field at the B40, the ball is snapped. Player B1 is running to the B35, then the QB comes around to that side of the field, the QB gets hit, loses the ball, B1 recovers the ball at the B35, turns around, and scores a touchdown.
Is the foul for illegal participation enforced from the B35?