It's about saving lives? This asking if your neighbors have guns is about saving lives. If you find out your next door neighbor has a gun, CALL THE POLICE IMMEDIATELY!
I agree with your assessment, and I'd like to add that this is also about shunning "unsafe" families. When your PTA or PTO gets together, or your church group, one thing that gets passed around is which parents own guns. This info is used to decide whether or not your kid is allowed to play with other kids. Read up on PAX's stuff. While they do not say this is desirable their plan makes such a thing possible.
I have been approached at church and told, "just so you'd know", that the so-and-so family has guns in their house. I asked my informant if they had heard of PAX and of course they had, even had one of the downloadable flyers.
Society is safer when criminals don't know who is armed, I said, ending the conversation and no doubt being added to the list. Had I been more clever I would have shut up and tried to find out if there was a real list, paper or spreadsheet, that someone was maintaining. Perhaps another FReeper can do this and report?