Two interesting posts from Canada
I am not pretending that this would not create other problems, but the casualty rate in ALL those cases would likely have been reduced were more people carrying guns. The offenders could have been defended against and eliminated much faster than by waiting for the arrival of the police. Wild west? Yup! In these specific cases likely effective. Problematic - yes. Let us have an honest discussion and not pretend these explosions are a case for gun control - in many ways they are the opposite.
Of course, I would point to the evidence on how permit holders actually behave in the US to assure him that the dangers aren't what he fears that they might be. For information on this please go to this, this, and this posts.
2) For an interesting picture of a shopping bag, please see this blog.