I would not take USD either. Transfer drivers have been willing to take CAD if I don't have JMD upon arrival.

I thought I'd read recently that ATMs dispense up to 30,000 per transaction, but you can repeat transactions until you reach your maximum daily withdrawal limit (provided there's enough cash in the machine). As mentioned, always good to take enough CAD cash to exchange for JMD at a cambio in case the ATMs have issues.