Most Americans are aware of the protections afforded by the U.S. Constitution’s fourth amendment against unreasonable searches and seizures. In general, this means that the government cannot search your person, home, vehicle, or computer without probable cause to believe that you’ve engaged in some criminal act.
What many don’t know is that there are quite a few circumstances that the Courts, over the years, have deemed to be exempt from this requirement. One of those occurs when you enter the United States at the border. In April of this year, the Ninth Circuit Court of Appeals upheld the right of Customs officers to search laptops and other digital devices at the border (the definition of which extends to any international airport when you are coming into the country) without probable cause or even the lesser standard of reasonable suspicion. The Electronic Frontier Foundation (EFF) and other groups strongly disagree with the ruling. You can read more on the EFF Web site (http://www.eff.org/deeplinks/2008/04/no-cause-needed-search-laptops-border).
Meanwhile, be aware that even though you’ve done nothing illegal and are not even suspected of such, the entire contents of your portable computer, PDA, or smart phone can be accessed by government agents when you enter the United States. So if you have anything on your hard drive that might be embarrassing, you might want to delete it before crossing the border.
See the article (pdf) from TechRepublic: 10 ways you might be breaking the law with your computer