Now, when to analyzed that Blockbuster situation, you said "Maybe the guy was just going to take the money and run and didn't intend to shoot unless someone put up a fight."
You are spending time considering the thoughts and intends of a criminal.
1. The man in the store had to make a quick decision as to what to do.
2. There is no way to know the intents of anyone, you can only make assumptions. If I see a man walk into a Blockbuster with a shotgun, what conclusion should be drawn?
About assault weapons:
My response to you Warbler depends on how I read into what you wrote.
"do we need assault rifles?"
--The invention of the assault rifle was unneccessary. In that sense we did not ever need assault rifles.
"do we need assault rifles?"
--Since they do exist and criminals often do not stop to question the legal implications of having one, I can see where the public would want to feel protected and want to be allowed to use them as well.
About aiming for the leg:
I will give you that someone shot in the leg can fire back, but aiming for the chest or stomach is not the answer either.
A shot to the chest can do serious damage to the heart or lungs. If the shot is "lucky", the ribcage can actually work against the body. A bullet can ricoche around inside doing lots more damage.
A shot to the stomach threatens the liver, intestines, plenty of other lymphatic organs as well (not to mention the stomach itself. I've also heard that the stomach is the most painful place to be shot.
Hitting them just about anywhere will leave them in enough pain to keep them from returning fire for at least a few seconds, the leg is non-vital and prevents them from standing.