A top executive suddenly dropping off the radar would be alarming for any company. But in China, it's become a disturbingly familiar situation. The latest example is Wu Xiaohui, the chairman of a major insurance company that owns the Waldorf Astoria in New York and recently held talks with the Kushner family over a Manhattan office tower. He is reported to have been detained by authorities on Friday as part of a government investigation. His company, Anbang Insurance Group, said in a short statement that Wu "cannot perform his duties due to personal reasons."