Does your child watch pro sports? If so, you should be watching with them to make sure any inappropriate behavior can be discussed. Kids look up to the pros, and will imitate their actions and words. Remind your child that even pros make mistakes, and should be held accountable for their actions.
Watch closely for any "copycat" behavior in your child's activities. These should be addressed immediately.
The pros can be a great example for your child - of good AND bad behavior!