I'm guessing that most of you have heard about the Westchester County, New York newspaper that published a comprehensive list of all the households in Westchester, Rockland, and Putnam counties that were listed with the government as containing a resident who holds a concealed-carry permit. The article, by Dwight R. Worley, is here. Worley, by the way, is himself a gun owner. The newspaper is the Journal News.
There has been a great deal of understandable outrage about Worley and the Journal News shredding the owners' privacy. Surprisingly, though, I haven't seen anyone suggest something else: that the now-public information could have implications for future crime. Now reasonably sophisticated criminals can have an idea about which households to avoid in the future. Granted that there are probably many more households whose residents own guns and no concealed-carry permits. They can defend themselves from home attacks too. Still, now potential criminals can know who is virtually certain to have a gun in his house.
It would make sense, therefore, for someone to start gathering data on crime on households and, using a difference-in-difference approach, see if there's any effect on crime. My prediction: the revelation of information, while it is a gross violation of privacy, will make those households somewhat safer.
Of course, you could argue that a sophisticated criminal could have used freedom of information laws to get those data anyway. But such criminals would be leaving a bit of an electronic trail and, therefore, might have hesitated to do so. No such problem now.
I wouldn't be surprised if a Ph.D. economics student somewhere in the Northeast is already contemplating such a study.