They do announce people have DA's themselves when they have written no such letter
Action such as that used to be reserved for those who had joined the army or some State Organisation that was incompatible with their beliefs, and they were not legally empowered to d/f a person who was simply doing what the State wanted . I was told it originated at times of war.
Now however it has spread to other cases such as those taking blood or others that they may not be able to pin down to a d/f charge.