From what I've gathered from various friends and acquaintances working in law enforcement and criminal justice, the vast majority of criminals are really not the kind of intelligent folks who would do such research. That's why they're criminals. The sophisticated type you see in television is very rare.

This may be an effect, but while some criminals want to avoid a confrontation with a gun-wielding resident... others want to steal guns. By helping criminals self-sort to the right targets for the risks they prefer, the net effect on crime/safety could be negative, by shifting break-ins to where they are most likely to succeed.

Two variables of risk that factor into a criminal's decision:

1) Is the house occupied? 2) Are the occupants armed?

Providing an answer to the second question only helps the criminal by letting them know that they can perform an armed robbery with no resistance.