Customer brings $5,000 in currency to the bank and deposits the cash into their checking account. From this same checking account, they write a check for $32,000 for a Cashier's Check. Is this transaction subject to the $3,000 recordkeeping requirement?

Yes. FinCEN considers the $5,000 as currency used in the purchase of a recordable monetary instrument purchase.

I would retain the information, although some would not if there was $32,000 already in the account. Since this info doesn't get reported anywhere, but is retained and reviewed by examiners, I don't over-analyze the situation. We haven't been told not to by our regulators.