From the Article:
"We are investigating," Iwata said of reports about the Wii's strap coming off as players swung around the controller, at times causing the remote to fly out of their hands.
Players use the Wii remote like a tennis racket, sword and other devices to play games.
"Some people are getting a lot more excited than we'd expected," Iwata said. "We need to better communicate to people how to deal with Wii as a new form of entertainment.""