Rockstar was pretty ticked to discover that The Simpsons Game parodies Grand Theft Auto; as EA's Matt Selman puts it, when Rockstar saw the Grand Theft Scratchy poster, they "spazzed out like little babies."
In an episode of Game Head, Selman explains that the idea that it was pretty absurd for Rockstar to worry that anyone would actually confuse the fake game of Grand Theft Scratchy with the real Grand Theft Auto:
We couldn't get our game out in time, so we're afraid that the gamers — who are not morons — are going to get confused by an Itchy and Scratchy poster of Grand Theft Scratchy - they're going to think that's the same thing as Grand Theft Auto.
Selman is actually a big fan of the GTA series, saying "I'll be the first person in line to play Grand Theft Auto 4...in five years when it comes out." Oh, burn.
Source: WIRED Blog