If this occured while the engine was running, the engine could stop. Also, if the vehicle were being operated at night, the lighting system could shut off, increasing the risk of a crash.
Vehicle description: Passenger vehicles. The nut that secures the main positive cable to the positive battery terminal clamp was not tightened properly, allowing the cable to loosen over time. If this occurred, the cable could ultimately loosen to the point where electrical continuity could be interrupted.