Bucketrunner,
I am not sure which specific ride you are referring to, but the only time a zero score or deduction is given is when the rider uses 2 hands or uses the romal other than what is allowed by the AQHA guidelines. A simple "pumping" of the arm is not grounds for a disqualification score, nor is it grounds for a penalty deduction. You will see this sometimes on the large fast circles and on the run up to the sliding stops as well. It would be a lot less noticable on the small and slow circles.
I will make note that the first ride of the championship round, by KSU's Warner, had numerous performance reductions in her scoring. Cooper actually scored the ride at a 7 point reduction, while Dudley scored it with a 3 point reduction. KSU's Zimbelman received a zero score as well in the championship round for being off pattern, both in reining.