Reese Witherspoon warned the police officer ... "YOU BETTER NOT ARREST ME" ... on the night she was busted in Atlanta -- and TMZ has the dash cam footage of the entire unbelievable incident.
During the arrest, Reese also told the cop she was pregnant and needed to pee. She later confessed on "GMA" that she panicked and said "crazy things" because her husband was being arrested.
Have you ever been arrested? How did you react?