The TSA won't let you board some flights unless your devices turn on
 

You know how airport security will occasionally ask you to turn on a phone or laptop to prove that it isn't hiding explosives? Well, that's no longer just a rare inconvenience -- if you take certain flights, it's mandatory. The TSA now requires that...

http://www.engadget.com/2014/07/06/t...=rss_truncated