There have been patents filed by game companies themselves that have been discovered that illustrate, by the company's own admission, that this is being done. Take 2, EA, and Ubisoft come to mind, and I would be utterly shocked if Blizzard wasn't doing it. It is painful in how naive the notion that "we don't know for sure" is.
"The assumption that animals are without rights, and the illusion that our treatment of them has no moral significance, is a positively outrageous example of Western crudity and barbarity. Universal compassion is the only guarantee of morality."