I'd think if you're worried about being attacked by people wearing armor you should either start carrying a rifle/shotgun, or re-evaluate your career.
It would be hard - in a defensive situation - to make use of Mozambique style drills. People move fast, and one would assume that a robber that thought to bring armor would also have a gun. Plus, as civilians we can't start shooting until we're pretty sure that our lives/safety (or property in some states) are in danger.
"2 to the chest 1 through the ocular cavity" sounds great on the internet, but starts to fall apart when you look at the actual logistics.
si vis pacem para bellum