Should American grocery shoppers carry 30-shot rapid-fire rifles when they go grocery shopping? It might discourage mass-murderers.?

I have NEVER seen a shopper carrying a large-magazine pretend military rifle inside a retail store, let alone mow down peaceful, unarmed citizens. Those carrying WMD's and their apologists claim it's for self defense and is their right. This right should extend to ALL citizens and they should exercise their right to carry in order to reduce the number of murders by armed maniacs. 

Don’t they already do that with open carry and stand your ground.

if you're going to be a loathsome troll that exploits mass murder to make petty troll points.....shouldn't you at least put a little effort into it?

They aren't allowed in "gun free zones", EH Answar"