Question: On July 5, 2005, Dr. Smriti Nalwa took her nine-year-old son and six-year-old daughter to Great America amusement park in California where they went on the park's Rue le Dodge bumper car ride. The ride consisted of small, two-seat, electrically powered vehicles that moved around a flat surface. Each car was ringed with a rubber bumper and had a padded interior and seatbelts for both driver and passenger. The driver of each car controlled its steering and acceleration. Nalwa rode as a passenger in a bumper car her son drove, while her daughter drove a car by herself. The bumper car in which Nalwa was riding was bumped from the front and then from behind. Feeling a need to brace herself, the plaintiff put her hand on the car's "dashboard." According to her son, "something like cracked" before his mother cried out; her wrist was fractured. The Rue le Dodge ride was inspected annually for safety by state safety regulators, and was inspected daily by the park's maintenance and ride operations staff. On the morning of Nalwa's injury, the ride was found to be working normally. Although other injuries had been reported in 2004 and 2005, Nalwa's was the only fracture reported. Nalwa brought a personal injury lawsuit against the owner/operator of the park.

a. What defense might be raised in this case? Explain.

b. Should that defense be successful? Explain. See Nalwa v. Cedar Fair, 55 Cal. 4th 1148.