How do you tell an OCer from an Assassin?
You can't until he points the gun at you and at that point you are dead.
How do you know if the person driving next to you has a driver's license or is not under the influence?
How do you know a pitbull won't attack?
How do you know the airplane you're on won't crash?
How do you know your house won't burn?
How do you know the bridge you're driving on won't collapse?
How do you know you won't be hit by lightning?
How do you know your gun won't explode on the next shot?