Flag vs. Whistle and Flag, Linesman, NFHS

[Robert Goodman]

Originally Posted by johnyd

2. Illegal Motion, when one A player in motion moves towards the line of scrimmage prior to the snap

...and continues thru the time of the snap....

Flag, but NO whistle.

3. Illegal Motion, when two A players go in motion at the same time

...and do not subsequently come to a stop for a second, before the ball is snapped...

Flag, (Whistle or not Whistle?)

No whistle.

The way it works in all the major codes is that if there's some condition that becomes illegal at, and only at, the time the snap begins, there's no justif'n for flagging, let alone stopping play, until the ball's snapped, and also the rules makers didn't want the snap itself to trigger the condition for a whistle. So AFAIK in all major codes these "fouls occurring at the time of the snap" all require play to continue.

But those are cases where part of the condition is something occurring prior to the snap, and then the snap makes them illegal. There are now cases that require whistling because of something that occurs only during the snap, constituting illegal snap or interference with the snap. The fiction is that the ball remained dead, even though a short period of time must've elapsed starting when the snapper moved the ball -- so it's a slightly retroactive dead ball.