When you cross the U.S. border, government officials can confiscate your electronic devices, search them, and keep them for a while for additional scrutiny, even when there’s no suspicion of wrongdoing. If you travel out of or into the United States, do yourself a favor and read the EFF’s comprehensive guide to what can happen, and what you can do about it. follow link
Wake On Demand in Snow Leopard
Putting your Mac to sleep saves power, but it also disrupts using your Mac as a file server, among other purposes. Wake on Demand in Snow Leopard works in conjunction with an Apple base station to continue announcing Bonjour services that the sleeping computer offers.
While the requirements for this feature are complex, eligible users can toggle this feature in the Energy Saver preference pane. It's labeled Wake on Network Access for computers that can be roused either via Wi-Fi or Ethernet; Wake on Ethernet Network Access or Wake on AirPort Network Access for wired- or wireless-only machines, respectively. Uncheck the box to disable this feature.
EFF Guide to Defending Privacy at the U.S. Border
To do this he does not need to have any reason, all he needs is to distrust or dislike you and to have his immediate supervisor back him up.
If you are not a U.S. citizen, you will want to arrange your electronic files so that you can be perfectly open and aboveboard at the border (and you will want to be pleasant and respectful no matter what).
Some years ago, Farley Mowat was denied entry. It happens that that Farley Mowat had been invited to the States to receive a literary award, and so was uniquely able to publicize his experience. He wrote a delightful book about it, "My Discovery of America." Mowat was barred on order from on high but now field officers with even less knowledge have the discretion to do the same.