“DO NOT ENTER”, the road notification reads. In a hurry, or snap decision, how many drivers would see the word “ENTER” and  proceed to drive into the direction they shouldn’t be?
Contrast that with the words “EXIT ONLY”. If you’re entering a facility, even the quickest of judgement calls would be able to assess not to drive that way.
As noted in Dr. Bob Rotella’s book, Golf is Not a Game of Perfect: the mind can’t comprehend the word “don’t”.

• Don’t hit the ball in the water
• Don’t think about how high up we are
• Don’t be so grumpy
• Don’t read the next line
• See, I told you

Think in the affirmative. Focus on what you want to do. The mind is a powerful engine for doing and a horrible machine for prevention.