Any unlock that is not just a reskin can affect all the game mechanics in the map. So they make a bunch of reskins with every map, and they all are variations of something we have seen before. This is important for some players to be rewarded with some cool unlock, but it usually not important for game play. If there is some sort of required item, it is usually provided somewhere on the map, such as lethal poison.
We could expect in some fantasy luxury resort like Disneyland, that the island workers are working behind the scenes below ground, and only to surface when needed.
Having said this, where the island workers sleep at night is not a consideration for game design. These are not meant to be realistic maps but maps designed for the purpose of game play. It is meant to be realistic enough to give you the immersive experience, but not meant to be substitute for reality.