Call me illiterate but that would be seen as either a mistake or as intentional rudeness. We structure instructions as requests for the sake of politeness, and

Call me illiterate but that would be seen as either a mistake or as intentional rudeness. We structure instructions as requests for the sake of politeness, and using a period here would come across as a very subtle mockery of this. In context it would imply some level of disdain for the recipient's right to turn down the request.