Zombies

This came up a while ago while Nathan and I were watching Resident Evil 2, during which some shots were fired into a crowd which may have contained zombies. It was the government doing the firing, and the crowd also happened to contain civilians. Some of the characters (good guys) were surprised that live ammunition was being fired. But zombies really don't care if you're shooting blanks at them. They just want to eat your delicious brains. They'll call your bluff.

Since then, you would not imagine the number of times it has seemed appropriate for us to repeat the lesson we learned from that movie. You'd think it would not be something that's widely applicable.