I believe there is a definite place for "warning shots" or "warning blows" as a tactic, and that includes any lethal weapon (gun, knife, stick etc.). Anyone who is skilled with a weapon should be able to use it with sufficient accuracy that it can be used to deliver non-lethal force. That may seem like a high standard, but high standards are necessary if you want to save human life. Ask yourself a simple question ... suppose you are a criminal suspect standing 20 feet from a police officer. You have been ordered to comply with a police request. But you are hesitating. Now imagine that officer fires one bullet into the ground, just 12-24 inches from your left or right foot. Accurate shooting. Do you honestly think you are still going to ignore the commands that are given to you?? Not if you are even slightly sane. The warning shot gives the officer the opportunity to demonstrate his command over the situation. I think it's highly regrettable that this type of policy has been dropped as an option in US law enforcement.