Developers should work to ensure that the system always contains the latest up-to-date copy of the registry. Although, of course, with the current level of technology, this is most likely impossible. But in the long term, developers need to focus on this. This will eliminate the possibility of any fraud within the service.
What if there is not any technology yet? That's right, you just need to make it yourself! It is on this path that the developers of Credits have gone and made a common registry of blocks, which always keeps the latest up-to-date copy of the registry! Thus, the possibility of fraud within the service is zero.
Sorry sir, I don't understand what is "the copy of the registry", but I believe developers of Credits will hear the voice of the community, why don't you join Credits telegram and discuss there? People are discussing various problems there, actively.