Something to keep in mind if your coworkers/startup cofounders/etc ever suggest implementing something like this.
Remember Apple’s mass location tracking ‘bug,’ where an iPhone file stored all your movements for years? In a (small) victory for the privacy side of things, Apple is to stand trial for failing to protect user data (for giving third-party apps access to the data) and mis-selling products (because the location-services switch didn’t stop the location tracking).
“Apple will stand trial over accusations that it misled iPhone owners by storing detailed information about their location even when location was switched off, a judge ruled yesterday.[…]
in this case, the claim hinges on the fact that switching off location services on the iPhone did not result in said services actually switching off. This was seen as a potential mis-selling of the device – installing an “off switch” that did not work.[…]
Phone users brought the case as a class action suit in 2011 after two privacy researchers discovered a file on the iPhone that stored its user’s movements in detail for periods of years. The location files were linked to the Unique Device Identifier, age, gender, name and credit card details of the phone’s user.
Third-party apps were able to make use of the data.”