Forget borders, it could be a problem for domestic flights in the US. I've had the TSA demand I give them my laptop for special screening. Presumably they 'thought' it was a bomb, they didn't ask me to turn it on. But had it been turned on, it would have been vulnerable.
what about using their device to install something onto your system rather than retrieving data from it? is it possible to do one of those mischievous flash roms from something like this?