When you look at your BlackBerry, you see a gadget full of important email, contacts and other files. Increasingly, authorities see admissible evidence.

In a small but growing number of cases, customs officials and police officers have been carrying out warrantless searches of the contents of laptops, mobile phones and other wireless devices. This spring, the 9th Circuit U.S. Court of Appeals in California ruled that "reasonable suspicion is not needed for customs officials to search a laptop or other personal electronic storage...