You could probably do this with some cleverness using Keychain or a custom URL scheme that an app with ads will only respond to if they have some ads cached. I'

You could probably do this with some cleverness using Keychain or a custom URL scheme that an app with ads will only respond to if they have some ads cached. I'm not 100% certain on this though as I've done very little with iOS. On Android this is obviously much easier. Just use a content provider as I mentioned above.