Gov. Jon Corzine signed a bill yesterday that prohibits the sale of a children’s toy called “Yo-Yo Waterballs” in New Jersey. The toy has been blamed for injuring hundreds of children nationwide and has already been banned in Canada, Britain, France, Switzerland and Australia. Violators of the New Jersey ban, which goes into effect in three months, face a fine of up to $10,000 for a first offense and up to $20,000 for all subsequent offenses. Yo-Yo Waterballs, which also are sold under various other names, are squishy toy balls on a bungee-cord string with a finger loop at one...