They are not asking for proof of departure. You simply walk up to the first outside tent, there are several airline reps there. They take your ID, check your name against the passenger manifests, and give you a ticket. You then proceed into the new building where you give your ticket to the person at the booth. Then you walk down the hallway where they weigh your luggage and apply the proper sticker to it. At this point you go through the door to the ticket counters, stand in line for your carrier and wait your turn. They print your tickets, take your luggage, unless it’s carry-on, and you can either chose to go back outside or proceed to security. VERY EASY, they don’t ask one word about proof of departure.
This is the first time in all of our years going to ST. MAARTEN that we have not received a stamp coming into or leaving.