The worm guard, popularized by the great Keenan Cornelius , is one of the most well-known techniques that make up the "New School" of BJJ. The New School has many advantages and disadvantages. Most importantly, new moves add richness and excitement to the game, but on the other hand, they sometimes stray from the classic principles of BJJ and can cause the game to get frozen and stuck. Having said that, as soon as a new move becomes part of the general knowledge of BJJ, practitioners and instructors have a responsibility to learn it. The privilege to decide which moves to use and which not is only earned by having learned and used the move, and in doing so gaining a full understanding of it's uses, effectiveness, and counters.