I\'ve just received this message from Google Play but I\'m not collecting the Advertising ID.
Reason for warning: Violation of Usage of Android Advert
Today many developers are getting this same issue. I also got this issue. I didn't collect any sensitive data, I am not even showing ads to my users. In your case the Crashlytics lib could be an issue. It deals with advertising IDs. In the mail they mention the required action:
Action required: Add a privacy policy to your store listing and app
So I think all of us should add a privacy policy on the store listing as well as on the app. Before taking the action we should go through the related privacy policy. Here are some links from where you can get help:
Privacy policy to upload an app
Usage of Android Advertising ID
Developer Distribution Agreement
Developer Program Policies