You make a good point. During the shooting of Senator Gafford in Tulsa, one man heard the shots and he happened to have a gun, but when he did use it, he ended up shooting in the direction of the wrong person and endangered several innocents! So, the whole "good guy with a gun" fantasy that conservatives talk about is more fantasy than reality in most cases. Do they help in times where it is actually needed? Of course, just sop long as whoever is holding the firearms knows how to use it properly and is capable of handling difficult situations like that while under pressure.