The article doesn’t explain how to install an application that can be uninstalled using the "X" button in the Mac Apple Store (MAS). Instead, it explains how to activate the button in apps that are already installed. So, your theory that Apple might eventually prevent the installation of an app is not relevant here, as the article isn’t discussing that at all. However, it’s possible that Apple could update the verification process for the MAS app to check for an empty "receipt" file and then prevent the application from starting until the user deletes that file. This seems like a reasonable expectation to me.