It looks like the new umpire position (behind the offense) will prevent them from seeing holding by the defense. Defensive tackles must be licking their chops because of this new rule. "The latest tweaks, made after a conference call that included members of the league's competition committee, include requiring the umpire only to be standing behind the deepest member of the offense, and quarterbacks can look at officials near the sidelines to get the go-ahead to snap the ball, rather than turn around and look for a signal from the umpire."