While he realizes that clubs and extra-curricular activities are very important to the average school career, Masato is uncomfortable with committing to any sort of social group.  He's relatively certain that most people don't want him around anyway, not to mention the fact that it'd take time away from his lucrative enforcer job.  He<em>is</em>a better than decent martial artist, however, and many of the martial arts clubs would love to have him if most people weren't afraid of the idea of sparring with him.  That said, he would probably consider it if someone seriously approached him about joining their club.