Not necessarily. In theory, they could have you dead to rights on video/floor surveillance from start to walking out the door and simply didn't stop you for one reason or another. I had some cases in my day where I had to break off the stop but I had everything I needed for it.
Since it hasn't been said yet, STOP STEALING! You are helping drive up costs for the rest of us, not to mention jeopardizing your future when you get caught.

