Z:gnu-www-ja-the-root-of-this-problem--9dfd08-The nastiest of the common res/en

The nastiest of the common restricted devices are cell phones. They transmit signals for tracking your whereabouts even when switched &ldquo;off&rdquo;; the only way to stop this is to take out all the batteries. Many can also be turned on remotely, for listening, unbeknownst to you. (The FBI is already taking advantage of this feature, and the US Commerce Department lists this danger in its Security Guide.) Cellular phone network companies regularly install software in users phones, without asking, to impose new usage restrictions.