There is a documented protocol for forcing the GPS on remotely, and sending the exact location. Cell tower triangulation has an accuracy of ~100m, GPS has an accuracy of 1m; cell tower connection is required to be able to communicate, GPS is not.
Therefore there would be no harm in having a physical switch for the GPS power; I can turn it on when I need mapping.
The NFC concern is not about location, but about money and exploits. The "mobile wallet" initiatives have a charge that can be drawn without authorization, 25 eur in one of them. This means that should a crook be able to turn it on via an exploit, he can repeatedly charge you for 24,99 and drain your account from several dozen meters away, with you none the wiser.
Battery life of a week is pushing it. Most phones only last a day of use. Stand-by is another matter.
That would finally remove the need to recompile the NDK part of an android app for every cpu architecture it should run on ;-)