Rule changes this year are all about safety.  The most noticeable one is improper equipment.  Should a player not have proper equipment on a play, the calling official will blow his whistle and stop the clock and the offending player will be sent off for one play just like they lost their helmet.  Should the player come back without fixing the issue, he should not be allowed to substitute in as all substitutes are supposed to be properly equipped.  If you have a repeat offender, an Unsportsmanlike flag may be thrown at the official’s discretion and can be charged to either the player or the head coach.