I thought it was played brilliantly, even if unintentional. Social engineering means having people give up information that you aren't directly asking for, which is exactly what happened. It might have been pure luck, but as Edna said on The Incredibles, "Luck favors the prepared, dahling" and you were prepared enough to catch the slip. Had you asked for a name up front your directness would have alerted the individual to clam up. Besides, I would hate to see anyone get burned for a gem of a sincere slip. Go AFPW!