From last week (20 Nov 2015) Google has started to send an e-mail to all Google developers stating that they have to log into their account and declare if their Apps have ads. This is the e-mail from Google.
Hello Google Play Developer,
At Google I/O, we launched “ad-supported” labels for apps in the Designed for Families program. Today, we’re announcing the expansion of this program to all apps on Google Play. Early next year, users will start to see the “Ads” label on apps that contain advertising, both inside and outside Designed for Families.
By January 11, 2016, you must sign in to the Play Developer Console and declare whether your apps contain ads (such as ads delivered through third party ad networks, display ads, native ads, and/or banner ads). After this date, the ads declaration will be required to make any updates to your apps. Please note that misrepresenting ad presence violates Google Play Developer Program Policies and may lead to suspension. You can visit our help center to learn more.
While developers are responsible for accurately declaring ad presence in their apps, Google may verify this at any time and display the “Ads” label if appropriate.
If you feel your app has been incorrectly flagged for containing ads, please contact our policy support team.
So, before January 11, you are required to fill in that information in your App.
For Mobincube Apps WITHOUT ADs
For Mobincube Apps that have the "Remove Ads" service active you have to state that your App doesn't have ads and then you will get a warning telling you that your App contains advertising SDKs as displayed in the following picture:
This is because the Apps contain the SDKs even if the App isn't showing any ads. You just need to state that it hasn't any ads and then confirm the changes.
For Mobincube Apps WITH ADs
Just state that your App has Ads and then publish the changes.