You need to bleed the brakes only if you have symptoms of bubbles in the system, such as a squishy feel to the brake pedal. Otherwise, there's no need to bleed.
The maintenance schedule calls for flushing the fluid every two years or 24K miles, whichever comes first. This is VERY important. Brake fluid absorbs moisture over time, and this lowers its boiling point. That's why you need to flush the fluid.
If you're driving the car hard and/or taking it to the track, you should flush the fluid even more frequently. I have mine flushed annually in the spring (my car sits unused for 4-5 months in fall-winter). If I were tracking it year round, I would have it flushed twice a year.
The system is not entirely sealed. I'm not sure about other parts of the system, but I think there is not a tight seal on the cap on top of the fluid reservoir, for example; this allows the fluid level to fluctuate between the min and max levels as the thickness of the brake pads varies when they wear.