It is a pitfall for many harpists who think they can never change a fingering in a piece. It is one thing if it is by a very exact and particular composer such as Salzedo, and another in most others. My teacher always said, you don’t divide the music between hands like on the piano on the harp, you play with whatever is available that is most comfortable, and use your ear to create unity of sound. That works well with modern music, certainly.
I don’t think the students should be penalized, unless they simply didn’t practice, but maybe the teachers should?