Are you prepared for an overwhelming force coming through your front door?
Folks knew Katrina was coming for days. Yes, they couldn't foresee the dikes breaking , but there
Was advance notice about gun confiscation. Granted most didn't have available communication as power was out, but a lot of folks knew, and gave them up without a fight. In fact, not one person died resisting the gun confiscation. One little grandma got slapped around, but in the end they got her gun.
One thing that came out of Katrina was a slew of laws prohibiting the confiscation of firearms during an emergency.