Given that you were replying to a comment specifically about open source, that wasn't clear. Also if an app is closed source, you have to wonder how the cloner obtained the source in order to re-skin it? Is that sort of industrial espionage, or code decompilation of iOS apps common?

You also have to wonder how Apple would know? There are almost half a million apps on the App Store, detailed code analysis of the app binary and comparison with other compiled app binaries on the store is hard enough on an individual basis, and trivially defeated by code obscuration, let alone at app store scale.

What are you suggesting Apple, Google, Microsoft, Amazon and other store operators should be doing?