Final answer:
When a foul occurs simultaneously with the snap in football, the exception to the all-but-one enforcement principle is that the foul is disregarded and the down is replayed.
Step-by-step explanation:
In football, when a foul occurs simultaneously with the snap, the exception to the all-but-one enforcement principle is that the foul is disregarded. This means that the down is replayed and the offense retains possession. The penalty for the foul is not enforced, and the down is replayed from the original line of scrimmage.