I was watching one of those competitions once and one of the dogs, in the middle of a full speed sprint between obstacles, suddenly put on the brakes, slid to a halt, and took a massive dump right in front of the crowds and cameras. The commentators tried to talk around it and express embarrassment for the owner/trainer while she acquired a paper towel and picked up the droppings. One commentator though, with a very upper crust British accent, just summed it up by saying, "Well, sometimes a dog just has to do what a dog has to do...."!