The Department of Homeland Security has outlined what we've all known for some time - that border agents are allowed to snoop through files on your computer, mobile phone or any other digital device.
Officials can keep documents or computers, take them to an off-site location, copy the contents and share the data with other agencies. If there is no probable cause to keep the information after this it must be destroyed. A San Francisco court upheld the right of border agents to search laptops even without reasonable cause back in April.
Officers who find business or commercial information "shall take all reasonable measures to protect that information from unauthorized disclosure". But officers cannot read, or allow others to read, "correspondence contained in a sealed letter class mail (the international equivalent of First Class) without an appropriate search warrant or consent".
However, letters carried by individuals or private carriers like DHL or UPS are not considered mail.
Border officials are told to seek advice if they believe material may be subject to attorney-client privilege.
If this all sounds draconian, don't worry. The border folks are also told that in the course of every border search, they "will protect the rights of individuals against unreasonable search and seizure." So, if you're travelling to the states on business and don't like the border patrol rummaging around your laptop, feel free to start quoting the fourth ammendment at them. We're sure it'll pull them up in their tracks.
The full guidance is available here (pdf). ®