Interesting to see how this plays out in the long term. The real telling, or should I say damning question is just now many apps make a lot of revenue off tracking users across other apps and websites. Obliviously companies like Facebook and Google have a vested interest in this because of ads and analytics but for most regular applications the difference is down to how the above pay out from their services.
Personally, I don't think it is an unreasonable expectation that users should be made aware of where their data is being sent. Online most people should already beware of tracking cookies and such. But the same expectation is not there with moving between apps; perhaps it should be given the prevalence of large ad networks.