Hmm.. maybe Scarface? It is kind of a stretch though.
My memory is a little fuzzy (I should rewatch it) but when Tony was in New York to bomb the car he called it off because there a kid in the car. He may have said something with regards to "We didnt' say nothing about no kids".
On a little side note, does anyone else think South Park has gotten much better as it has progressed? At first it was just crude humor and shock factor.. now though they do more movie references and make fun of events in real life without shame (The Red Hot Catholic Love episode comes to mind). When I first started watching the show I liked it for the shock factor, now I'm starting to think these guys might be borderline comic geniuses. They're ability to make such crude parodies so funny and original is amazing.
Anyways, hope my movie reference helped... or at least maybe jogged someone's memory.