[mikesears]

From the 2009 NFHS Handbook:

False Starts and Illegal Motion
A false start includes a shift or a feigned charge which simulates action at the
snap, or any act clearly intended to cause Team B to encroach. It is a false start if any Team A player on his line between the snapper and the player on the end of their line, and who has placed his hand on or near the ground, moves his hand or makes any quick movement.

A false start is closely related to encroachment. It is a dead-ball foul. A false
start occurs prior to the snap. After the ball is ready for play and all players are ready for the snap, no offensive player shall make a quick or jerky movement before the snap. Any such motion is a false start. It is a false start whether or not the defense is drawn into the neutral zone. The purpose of the restriction is to discourage action designed to cause defensive encroachment.

Illegal motion is different from a false start as it is motion at the snap. It
becomes a foul simultaneously with the snap and is a live-ball foul. Play
continues and the offended team is given the option of accepting the result of the play or the penalty from the previous spot.

No more than one offensive player may be in motion at the snap. The player
in motion may not be moving toward the opponent’s goal line at the snap. If an end goes in motion he must be at least 5 yards behind his line at the snap unless he stopped for at least one second and established himself as a backfield player.
================ pg 58 of the NFHS handbook ===========


So there is ONE of the fouls they are killing explained.