On the other hand, HN won't tell you it's a resubmit if the story isn't in memory (or in some cache? I'm not sure of the details) so it's still possible to subm

On the other hand, HN won't tell you it's a resubmit if the story isn't in memory (or in some cache? I'm not sure of the details) so it's still possible to submit a dupe. Submitting a link or searching on hnsearch.com is pretty cumbersome just to check if something's been submitted already.