"Absolute insurer rules" and "trainer liability rules," common in horse racing and other equine sports, presume that trainers are responsible when their horses test positive for illegal substances. In effect, the rules make trainers guilty unless proven innocent.
The effect of this presumption is to shift the burden of proof from the governing body to the trainer, who must prove innocence by showing that he or she did not negligently administer a prohibited substance to the horse or did not negligently allow someone else to interfere with the horse. These rules can result in the imposition of a penalty against the trainer and/or the horse’s owner without actual proof of guilt.
Courts have uniformly upheld the absolute insurer rules, despite the fact that they appear to violate the due process of law.