If anybody is interested, here is the iPhone Software License Agreement:
http://images.apple.com/legal/sla/docs/iphone.pdf
On the very first page, there is a rather large paragraph describing the use of non-personal location data.
By using any location-based services on your iPhone, you agree and consent to Apples and its partners and licensees transmission, collection, maintenance, processing and use of your location data and queries to provide and improve such products and services. You may withdraw this consent at any time by going to the Location Services setting on your iPhone and either turning off the global Location Services setting or turning off the individual location settings of each location-aware application on your iPhone.
Great, so all the users who have their location services setting switched off shouldn't have any hidden files, right?