A U.S. federal appeals court ruled yesterday that customs officers can search your laptop at the airport for absolutely no reason. No need for suspicious activity. You don’t even have to make a bomb joke (see below). Even if you look and act as innocent as a child, your laptop, cell phone and Blackberry are all fair game.

After a case involving a customs official finding porn on the laptop of a man from Orange County, California, the U.S. 9th Circuit Court of Appeals in San Francisco decided that customs officers don’t need reasonable suspicion to search your personal and electronic belongings coming over border checkpoints.

Officers randomly searched Michael Arnold’s laptop at LAX on July 17, 2005, and found folders with child pornography. Arnold faces charges of possessing and transporting child porn and attempting to engage in illicit sexual conduct abroad with a minor, according to the ruling.

The U.S. Supreme Court has ruled that evidence is not needed to search at a border in order to protect the country’s “territorial integrity,” and airports count as borders. Therefore, the appeals court decided, a laptop is no different from a suitcase and can be searched at an international border.

If a police officer pulled over Arnold while driving, and Arnold looked and acted completely normal, the officer would have no right to search Arnold’s trunk. If the officer found child porn or drugs in the trunk, he would have a hard time using it as evidence against Arnold in court.

And yet, put Arnold in an airport, and all the rules change.