Here are ways you as a parent are allowed to encourage your child: root him on in a baseball game; hang his artwork on the refrigerator; bring him a glass of lemonade while he's doing his homework.
Here's a way you as a parent are NOT allowed to encourage your child: telling him to hit another boy during a fight, using skills he learned from studying martial arts.
Amy Meehan, of Indianapolis, learned that (seemingly obvious) lesson the hard way. She was charged with neglect and contributing to the delinquency of a minor after not only failing to break up a fight between her 9-year-old son and another boy in the neighborhood, but of actually - according to a witness - arming her son with a stick during the fight. Her four children were also removed from her home, pending a court appearance.
Meehan's story is quite different, natch. She claimed that the other boy was coming after her son with a stick, and that she encouraged her son to defend himself.
It's hard to get to the bottom of this story, because, according to Meehan's boyfriend, the fight stemmed from a "neighborhood feud," so I'm guessing that neither the participants nor the witnesses can be trusted to be completely straightforward.