Spoiler Space (scroll down)
Anyway...
So everyone seems to be pointing out that it was an error that Cartman's V-chip didn't shock him when he sang "Brian Boitano doesn't take shit from anybody...". Well, as explained in the demonstration, the V-chip (in South Park World) works like a lie detecter as your brain does something when you lie the same way as when you swear. Well, if you were on a lie detecter and sang a song with a line like "I'm super, thanks for asking" and you weren't, it wouldn't buzz since you are singing and the words come out differently, both audibly and mentally. You wouldn't consider yourself to be lying, they're just the words in the song. As for the swearing part, when the kids swear, there's a little part inside them that says "That's naughty and I like it" and it's that feeling that shocks Cartman. That feeling wouldn't happen while singing since those are the words and his mind is more concerned with keeping the tune, etc. OK, so now that I've proved that I have way too much fucking BZZZ time on my hands...