I don't race cyclocross, but I ride a Specialized Tricross Sport, which recently took an unexpected trip through some extremely heavy mud, that was like clay and sand mixed with water. The mud was so thick that it clagged up in huge clumps around the cantis, around the cranks, and even jammed between the rear wheel seat tube. It got so bad I could barely turn the wheels against the force of all the mud.
My buddy, on a Giant MTB with disk brakes, was fine.
What I'm wondering is, is aren't cyclocross bikes supposed to be designed for good mud clearance? Why don't they use disk brakes, considering they're apparently far superior in these kinds of conditions? Or is it just that the Tricross Sport isn't really a true "cyclocross" bike?
I'm not complaining, as I certainly have no intention of riding in those kinds of conditions again if I can help it, I'm just curious to understand the design of cyclocross bikes a bit better.
 See http://xkcd.com/geohashing