This is very true!!! No one trained in martial arts can always use it, or will have time to utilize their training. I know people who feel that they are invincible because of their martial arts training.
I'm a firearms instructor and at 20 feet looking down the barrel of someone's gun, you won't be able to use your training. A firearm is your best response, along with moving your butt!
Love the quote - used it before.