Buy your Exit Stamp upstairs in the airport when you ARRIVE - then its done; in the event you are pressed for time when you leave, the airline has a long check in line, you hit unexpected traffic going to SJO, or encounter what you did at the hotel.
Also change money at that bank (not the Currency Exchange) just a few feet away - saves you the poor exchange rates at hotels/casinos as well as the sometimes long wait times at banks downtown (you likely know this but some - newbi's - may not) - when I arrive, the last things on my mind are adding 2 tasks that can be handled at the airport in minutes.
