What do you assume when you see fromListN in a library?

Hey everyone: When you see fromListN as a function in a library, do you assume / presume it’s expecting an exactly N element list ? Or do you expect/tolerate other behavior ? Should it reject shorter lists? Should it truncate or reject longer lists? A corner case of this came up in some bug discussion I was having regarding vector, and I shall claim and or presume that most folks assume exact size with prompt rejection of too long or too short. Thoughts please ? -Carter