It's a real edge case, but someone could conceivably let their own domain expire and then register it anew and restore their website. It will be impossible to tell this apart from an SEO buying and restoring a website to use for link juice.
Yeah there's no shortage of caveats in this space. One could conceivably compare the outgoing links (being a search engine and all and having historical crawl data to compare against), but my hunch the cost of distinguishing between these two cases is going to be way out of proportion when compared to the benefit.
The DNS records would be completely revamped, or removed in that case.