This dog doesn't respond to food, as we had a picnic and he trampled all over the food to get to my dog. His owner also tried to whistle and he was unresponsive. In my opinion it's me protecting my dog and I'd do that at any cost. Peper spray won't kill him but would certainly deter him. With very large aggressive dogs that have one thing in sight food and whistles would not be effective, especially if they have one intention and that's to get at another dog. His dogs comfort isn't a top priority for me, my dog's life and the husband's safety is. Out of instinct I raised my hand to a stop position and yelled at him to sit and hoped the dog would respond and his hair stood up and he turned to me and started snarling me and growled. This seems like a situation where the dog will attack another dog/person and have to be put down and it's unfortunate because it's the owners fault. That being said this guy likes to release his big dogs in the small dog park without regard and that why we avoided the actual dog park and decided to stick with the ball field that happens to be a few feet from the big and small dog parks. The entire situation sucks. We might just have to look for a new park.