This is a hard one. About 25 year ago i had a dog who used to go out of his way to catch and turn his head on the lead dog only. The blinker placed on the left side of his muzzle fixed this problem. He never turned his head to a runner on the outside of him. He only started turning his head after being 'beaten up' by other dogs in the catching pen. There are many reasons and 'excuses' for dogs turning their heads in races, but i don't think we will ever see an end to this problem.