If you leave from or arrive into at least the 4th, 5th, or 9th Circuits (see map), your laptop can be searched at will, reports Orin Kerr, yet another talented law prof at my alma mater. This incident in Canada also involved a laptop scan as well as interrogation into possible libertarian sympathies. Of course, the scan of your laptop need not be restricted to child porn. Until we get the Fourth Amendment back, you can get some of its effect back by using TrueCrypt. Or just improve your odds of privacy by leaving the laptop at home and using something less conspicuous.