It is chance finds that I was thinking of - I was just considering the possibility of including, say, some "business cards" printed up with instructions for looking up the cache details online, so that if anyone did find it by chance they could take one of the cards and check out the record later. Just trying to make it easy.
Having some way of predicting what the "direct" URL would be might be a nice minor feature, but not strictly necessary (a more "generic" such card printed with instructions on using the cache search page to look up the cache by its title should work nearly as well for this purpose).
The "finders take a card from the cache and do something with it online later" idea is just a continuation of another set of thoughts I've been considering...but that's a topic for another thread.
"Given the pace of technology, I propose we leave math to the machines and go play outside." - Calvin