The current ‘Remove permissions’ option is useful but not always fail-safe. Removing permissions from the manifest is not something that an app will expect, so there’s a greater chance of the app crashing due to the system raising a permission denial error.
In the upcoming 1.4.7 update there are 3 new privacy options:
• Disable contacts access
• Disable calendar access
• Disable call log & SMS access
The main difference is that these options work without having to remove any app permissions. In this sense they work very similar to Android 6.0’s runtime permissions; if the permission is not granted (or was revoked) Android will simply return an empty contacts list or calendar event list rather than throwing an error.
With these options the clones basically don’t get to see any entries. Also, any attempt to insert or modify entries is silently ignored. Here some screenshots from the Contacts+ app.
App Cloner 