The IRS checks its records and the Social Security number of any claimants of the unclaimed funds prior to paying.
When I checked with the Sentinel, they told me the subscription remained open but there weren't any papers lying around unclaimed, yet you said there wasn't any forwarding notice filed with the Post Office.
Institutions may have different definitions of dormant account, lost account or unclaimed assets.
Around 1928 an apparition of an ancient Egyptian priestess was reported, and a newspaper reward for an overnight stay went unclaimed.
If your guest goes unclaimed for a certain period and you want to keep him, congratulations, you have a new cat.