At the very least, they should have informed the users of the risk they were taking... There are plenty of developers who could copy all sorts of data without y

At the very least, they should have informed the users of the risk they were taking... There are plenty of developers who could copy all sorts of data without you knowing. I think this is the whole crux of this issue. Hardly anything is private anymore. Today, people are willing to share data, but they demand control^ over it. If you just ask for the data, people will give it most of the time (especially when they went through the process of downloading your app and/or creating an account for your service). It's when you start doing things in the background that people start to question your motives & they feel like they have been conned into doing something they shouldn't have. A little transparency goes a long way. ^This is, of course, the hard part.