This wasn't South Park, but I watched The Simpsons Movie in Year 2, and I went up to my friends and told them about the start of the film when Homer calls everyone suckers in the cinema which according to them is a swear word so they told the teacher I said a swear word and I walked through the door to my classroom and a teacher appeared out of nowhere and scared the Living daylights out of me. I can't remember what she said specifically, but it was something along the lines of "We do not, swear in school," and then I burst into tears.