Not all reward and punishment is quite this obvious. Reward can be as subtle as the feeling of elevation that comes from doing a good deed. So, back to our busy store clerk example. I've been told that bullying is the number one social issue in children's lives today. They tell me they have a conflict education program.
Bullying is indeed a significant problem in many children's lives.
Instruction in karate, along with an accompanying conflict education program, can be a good option for some children. Many karate instructors teach conflict resolution skills and use this as their core focus, while others may not have this focus. Ask if you can observe a class and see if you feel comfortable with the instructor, the approach, and the response of the children. Since you know your child best, you will be the best judge of how comfortable your child might be in that setting. Young children may still have a hard time distinguishing fantasy from reality.