Such searches are not only intrusive, they are meant to freeze dissent in this country. Recent searches and confiscation of electronic media have happened to people such as Bradley Manning supporter David House, who had a thumb drive, laptop, and digital camera seized when he landed at Chicago's O'Hare Airport from Mexico last November. He's suing DHS, with help from ACLU of Massachusetts, who apparently have targeted him because of his work with the Bradley Manning Support Network. Bradley Manning is accused of leaking Defense Department information, supposedly to Wikileaks, and is currently being held in military custody at Ft. Leavenworth, Kansas, pending trial.
Another person who had his laptop confiscated back in February 2008, one of thousands of such Americans suffering such warrantless seizure, was freelance journalist Bill Hogan. A U.S. News and World Report article on Hogan's case noted that "an April  ruling by the U.S. Ninth Circuit Court of Appeals found that the Department of Homeland Security, which oversees Customs and Border Protection, does have full authority to search any electronic devices without suspicion in the same way that it can inspect briefcases."
It's not just journalists and activists who are having their electronic devices searched or seized, a Washington Post story from 2008 detailed such seizures going back to at least 2006, and gave as examples a therapist and a marketing executive. One person had their daughter's personal calls erased from her phone. Another person, a tech engineer, was forced to give up his password and stood helplessly by as DHS officials copied down his website viewing history.
"It's one thing to say it's reasonable for government agents to open your luggage," said David D. Cole, a law professor at Georgetown University. "It's another thing to say it's reasonable for them to read your mind and everything you have thought over the last year. What a laptop records is as personal as a diary but much more extensive. It records every Web site you have searched. Every e-mail you have sent. It's as if you're crossing the border with your home in your suitcase."Other lawsuits have been filed against the government policy, and Electronic Frontier Foundation has also been active in supporting these legal actions. Meanwhile, according to Computerworld, the Ninth Circuit ruled again just last April that "Laptop computers and other digital devices carried into the U.S. may be seized from travelers without a warrant and sent to a secondary site for forensic inspection."
From the TCP press release:
U.S. Urged to End Border Searches of Electronic Devices Without Reasonable Suspicion
WASHINGTON -Today, The Constitution Project (TCP) called upon the Department of Homeland Security (DHS) to discontinue its policy of searching electronic devices-including laptops and smart phones - at the border without reasonable suspicion. According to a just-released TCP report, between October 1, 2008 and June 2, 2010, over 6,500 people - almost half of whom were U.S. citizens-were subjected to searches of their electronic devices upon crossing the international border.
The report was developed by 19 members of TCP's bipartisan Liberty & Security Committee, including William S. Sessions, a former federal judge and Director of the FBI; Asa Hutchinson, former head of border security for DHS during the George W. Bush administration and former Member of Congress (R-AR); and Mary McCarthy, a former CIA official.
According to TCP Senior Policy Counsel Sharon Bradford Franklin, "Searches of our laptops and smart phones - without reasonable suspicion - can easily result in a breach of our privacy rights, given the amount of personal information we carry on those devices. Courts have historically recognized a limited exception to the Fourth Amendment permitting routine searches at the border, but the scope of those searches has vastly expanded given the storage capacity of electronic devices today. It's a classic example of technology outpacing our legal system, and the government must reform its policy to restore Fourth Amendment protections."
The report cited such search practices as accessing email accounts, examining photographs and looking through personal calendars. In some cases, electronic devices were confiscated for as long as a year. The report recommends that in the case of U.S. persons, officials should be required to obtain a warrant based on probable cause before continuing a search or retaining copies of electronic data beyond 24 hours.