[Al Skierkiewicz]

Erik,
I have to disagree. While the fuse internal to the Crio is meant to protect parts of the internal Crio electronics, electrical faults on the robot can cause real voltage drops across the #18 wiring used to feed power to the Crio. This is well documented over the past two years irrespective of motor issues. With these faults current merely flows through the chassis of the Crio to the negative lead and out the power connector.
Isolated (electrically) frames have been part of the rules to prevent robot to robot electrical faults from causing sparks and fire on the playing field. The potential in this scenario is the ability to provide up to 24 volts at high current, through parts of the frame and any wiring that might be in the circuit. Anyone who has been around more than a few years remembers the spectacular displays, smoke, hot (incandescent) wiring and yes even some flame that occurred prior to the inclusion of this rule.
Jason, the common myth is that robot to robot contact usually includes not only the robot frame but appendages or robot parts when tipped over, which have reached inside another robot. This is the second or third path that most people forget. In some cases, current will continue to flow even after the robot is disabled and the main breaker has been opened. It is why inspectors are so critical when checking the insulation on all electrical connections.