It seems pretty obvious in hindsight, but if an app requires eg your contacts, or access to running apps, or the ability to overlay stuff on other apps, or your location, phone number etc, they should carry an adult classification to call attention to those permissions.
Instead we classify Android apps by what the user can see or share with other users and third parties, allowing developers discrete, privileged access to our device or to collect any information permissions can expose even without disclosure.
Amazon will allow very serious permissions to accompany childrens apps like this rated as Guidance Suggested, one notch above All Ages because of advertising. Take out those ads and theyll bump it up to an All Ages despite this little easter egg: Get information about the currently or recently running tasks: a thumbnail representation of the tasks, what activities are running in it, etc.
This puzzle on the Play Store can monitor the wifi connections you come in range of and Google classifies it as safe for Everyone, the most trustworthy classification rating they offer, even after Google got slammed by privacy groups in Europe for collecting that same information!
Trend Micro has a piece on the most popular Android permissions exploited by malware. They are just some of the permissions that should trigger deeper customer scrutiny, and should be handled with particular care in childrens apps to maintain COPPA compliance.
If youve never published an app before heres the poll Amazon (scroll down for Googles) uses to identify whether an app is suitable for all ages or requires some increased consumer awareness.
Googles is quite detailed, but far more concerned about whether you have a swastika vs potentially harmful or malicious permissions