17 Dec
2003
17 Dec
'03
11:17 p.m.
It may be that the phone can be "pinged" unbeknownst to the owner, but I'm fairly confident that if the phone is shut off, you're safe. The truly paranoid might consider stowing the phone inside some sort of RF cage, I guess, or maybe just throw it out the window :-)
I should have added in my remarks about registration that one very easy way to "ping" a cellular phone is to call it. If the phone is powered on and hears the page, it will automatically acknowledge it on the access channel (the mobile-to-base link that is also used to request a mobile-originated call). This will certainly reveal the mobile's location to the closest cell. Phil