Hi, thanks for the question. In general, this reduces the load on your firewall if you are already stopping traffic at the DNS level before the client tries to generate traffic on the URL that you need to block. It all depends on what network they used and what equipment they had at their disposal. I think that you are a good security specialist, since you have asked such a question, so I advise you to delete records from any place where there is no access-based system. If you grant temporary access on the device, it will be blocked by others anyway. If you can't sync them, then you need to delete them. Good luck to you!