In message , at
11:46:01 on Tue, 27 Aug 2013, John Rumm
remarked:
However, should you be using a laptop (let alone mobile) with wifi,
there are tools/databases that people can use which will quite likely
locate you within a few hundred yards.

I don't think you mean with wifi do you? Locating a laptop on wifi
should get you no further information that the IP address of the router
providing the wifi. The same information that you would get for a wired
machine on the same lan.

Yes, I do mean wifi. Not only did Google (and at least one other)
wardrive the entire country logging the position of wifi points, but
nowadays they keep them up to date by apps on mobile phones reporting
(without the users realising, and obviously only if both wifi and GPS
are enable) the identity of local wifi points, and the GPS co-ordinates
of the phone.
--
Roland Perry