The answer is no ... and for a specific reason. People in law enforcement, like people in the military, have ingrained in them from the first day in the academy a respect for rank. As long as the social engineer is posing as a sergeant or lieutenant—a higher rank than the person he's talking to—the victim will be governed by that well-learned lesson that says you don't question people who are in a position of authority over you. Rank, in other words, has its privileges, in particular the privilege of not being challenged by people of lower rank.