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At first I was all "I'm going to stop saying 'rain cheque' because it's from baseball and baseball is lame" but now that I've found a Wikipedia list of idioms from baseball, because there's just so many of them, I have rescinded that opinion. https://en.wikipedia.org/wiki/Glossary_of_English-language_idioms_derived_from_baseball#rain-check_(rain-cheque)
@levisan after World War II businesses adopted a lot of military idioms, many incorrectly since they don't really apply but it worked because so many of the workers had served in World War II. When military terms failed businesses often relied on equally misapplied sports metaphors to motivate "the team".