Many American technology companies insist that when their management and technical personnel visit China, they have their laptops checked by the security department before they leave, and after they get back. The travelers are advised to leave their smart phones at home, and buy a disposable cell phone when they get to China, and dump it when they leave. All this is to make it more difficult for the Chinese to hack their way into U.S. firms and steal valuable technology. U.S. government officials have been advised to take the same precautions. U.S. intel agencies apparently have long adopted such practices.