Both companies have denied wrongdoing: Facebook claims no problem because it tracks only to protect and serve you, while OnStar says everything's fine because it discloses the questionable behavior. These responses seem duplicitous at best.
Facebook and OnStar violated basic principles of cloud trust:
User data always belongs to the user
Private data always remains private
Transparency means integrity
For cloud providers, the answer is quite simple: be straightforward. If users logout or cancel their accounts, for example, stop tracking their behavior or movements. It's not hard! Cloud vendors that hide behind disclosures and excuses, rather than act transparently, appear creepy and sleazy.
Advice to CIOs. Before signing with any cloud vendor, carefully examine the fine print based on the three principles listed above. If you suspect the vendor is playing games, then go elsewhere. Trust, privacy, and transparency are your right -- don't give them away.