I teach sixth grade in the Bible Belt, so most parents would freak out here if Mr. King were part of the curriculum. This past year, during a "down time" while we were doing state testing, I offered to show a DVD of the cartoon The Regular Show. One girl said, "My parents don't allow me to watch that." Even if the kids know the words and watch TV programs that include the words or play those video games, I think, in sixth grade anyway, that we have to respect the parents' and kids' wishes to not show programs that have swearing.
However, in high school, so much good literature contains swearing and sex, I don't know how they could avoid it, and feel as if they're teaching anything meaningful to the students.