I always thought a rules "learning" mode in the emulator would be useful. While the mode is switched on, the rules are set to allow read/write everywhere. Run

I always thought a rules "learning" mode in the emulator would be useful. While the mode is switched on, the rules are set to allow read/write everywhere. Run your app and simulate a typical end user interaction. After you're done, the learning mode writes a set of the most restrictive rules possible based on the data read/writes from the simulated interaction. I think this would make a good starting point for new apps.