To my knowledge there is only one recorded instance of an animal killing a human inside of Yosemite National Park.
Can you guess what animal it is?
Nope, not a bear, keep guessing... not a mountain lion either... think more on the dainty, herbivore side... that's right, a mule dear. Most people would be shocked by this fact, but it is true. The deer around here are pretty "tame" in the sense that they aren't easily spooked by people, and go about their day while people are near. However, these animals are still wild animals, and for their sake and ours it is important to "keep them wild," by not feeding or getting too near them. It is important for wild animals to retain their wild instincts for survival.
Yosemite is a magical place and the "tame" deer make it feel even more like a Disney movie, but it is not. Please, please be respectful of the space and its residents. Follow the rules about food storage and not feeding wild animals. What seems like a magical moment for you can turn into a deadly situation for you or the animal. Don't be selfish, enjoy the animals from an appropriate distance, don't go traipsing through the meadows (they are protected), store your food properly, throw away your trash, and remember that approximately 4 million people visit this park yearly. If what you are wanting to do were multiplied by 4 million (or even several thousand), would it negatively impact the environment? If yes, then don't do it.