Just got off the Splendor this past Sun and the way it was explained to me make sense.
If you arrive early and your bags at loaded on the cart that takes them to the ship, then all those carts are loaded from back to front. So if you are arriving later then your bags would be toward the first of the loading area, thus unloaded in that order. Front to back, with the one that we loaded last are first to be sent to the rooms. Now that is what I was told.