In that case, I think I have do to come clean, I am Dutch. You're correct to say, one will not see these words used in newspapers or official contracts, but in literature it is the prefered form by a lot of writers. I think it is fair to compare these forms to English: "does not" in newspapers and other official documents and "doesn't" more or less anywhere else. These forms we learned from the very beginning in school.
We might introduce this later on as a bonus skill, but for now it is too confusing for non-native speakers. De/Het/Een are the first words introduced, so we can only adjust them there, meaning we'd be overwhelming people during the basics with abbreviations they might only need when reading Dutch literature.
I do believe that in the later lessons, 'n/'t are accepted as valid answers. :)