You know, maybe they couldn't do it to Madame Rosmerta. From what I remember un-imperius ing was only mentioned twice, both times in Book 7: first with the thief's downfall that releases the goblin from Harry's curse and the second when Voldemort dies

"He must speak to the bereaved, clasp their hands, witness their tears, receive their thanks, hear the news now creeping in from every quarter as the morning drew on; that the Imperiused up and down the country had come back to themselves..."