The MHSAA  rule adaptation is below......

MHSAA NECK GUARD REQUIREMENT- All players, including goalkeepers must wear a neck guard as required protective equipment.  Goaltenders are also required by NFHS rules to wear a flapper-style throat protector that must be separate, commercially manufactured, unaltered and properly attached to the goalie helmet or face mask.   
1.  The neck guard must be commercially manufactured and unaltered.
2.  The neck guard may be either separate or part of an undergarment with a neck guard extension.
3.  The neck guard must carry the BNQ certification mark.
4.  Coaches are responsible for all players being equipped properly.
5.  The penalty for a player that does not have a legal neck guard will be a team warning, the offending player sent from the ice (excluding goalies).   

Subsequent violations of this rule by any player shall result in a misconduct penalty.

Michigan High School Athletic Association