[Christ]

In my car, you can pull the hazard fuse and still start the car, and drive it around. It's just that 2 things happen:

1. You won't be able to use your Hazard lights... (duh, you pulled the fuse)
2. The CEL will light up while the ignition is on, but as soon as you shut it off, it will clear the code.

Pulling the hazard fuse essentially allows the ECU to delete it's running memory (when powered down) and re-upload the memory (on next power up) from the solid-state program (the one that never changes) in the ROM. It will not prevent the ECU from actually throwing a code though.

Switching the hazard fuse in my car is a quick way to reset it while tuning.. every time you do something to the car, it's a pretty good idea to reset it... as with any other ECU controlled vehicle.