If Nancy Lanza's gun info had been published in the paper

would the neighbors have reported their concerns about her son and his access?

Don't know the answer, but think this could be part of the reasoning used before they put that sort of info in the papers. Not even sure if Adam's mom would have met the criteria the paper used or would have been listed in the databases they had available.

Guess my real question is how strongly the general public is invested in being aware of their surroundings and how willing they are step forward before something tragic happens.

Jimmy Stewart might have just been bored and nosy, but he really did witness something from his rear window.