This is truly scary -- Laptops can be searched!
A recent 9th U.S. Circuit Court of Appeal allows the government to search, seize and download laptop data at border crossings despite the Fourth Amendment! Suspicion is not required. A warrant is not required. No protection is available for the individual under this ruling. Just one more liberty removed.
The panel suggested that travelers should no longer expect privacy!
Rules of professional conduct require confidentiality. ABA Model Rule 6.1 provides that "A lawyer shall not reveal information relating to the representation of a client ... " Thus, a lawyer should not have any information on the laptop about clients' matters. If that's true, then can a lawyer travel across the border with a laptop? Arguably not!
http://www.lawbizblog.com/admin/trackback/79682

Ed, I've never understood the Fourth Amendment to protect anyone from searches or seizures at the border. If you were carrying a briefcase full of confidential client documents, would you expect that to be immune from search by Customs? If not, why would you expect your laptop to be exempt?
The good news is that you can - and should, if it's on a laptop no matter where you tote it - encrypt confidential client data. Using common free tools, you can even camouflage the very existence of encrypted data. And of course, you've got it backed up somewhere safe, so if it gets to be an issue, you can mutter something about corrupted files and just delete it.