Coming from a staffer at the official SEGA forums…
You can enable catch-up for human players (in Multiplayer that is, both online and split-screen), but the aim is for the weapons and All-Stars to do the movement through the pack. Or you can turn it off – and see who is actually better at racing 
Too bad you can’t have that option for the single-player races. Maybe the rubber-banding issue won’t even crop up during single player. I sure hope that’s the case.
