When the domain drops, the DNS which matches the domain to the physical hosting no longer exists so there is no website and hence no more outbound links (from).
In bound links (to) have nothing to do with a domain expiring so will generally still be inplace but be broken.
Very true, I believe that is one of the reasons why Google originally got accreditation to be a domain name registrar so it could monitor and "reset" any existing links to expired domains... People do say that the links are discounted (or reset)..
Shags, if that had any merit, everyone would be doing it.