According to the American Humane Society, 56% of dogs that enter an animal shelter are euthanized.
Target was a stray dog in Afghanistan who thwarted a terrorist attack by ferociously barking at a would-be suicide bomber, preventing the bomber from entering a building before detonating his bomb, thereby saving lives. An American service member bonded with Target and brought her home to be his pet. She got loose from his house and ended up in an animal shelter in Pinal County in Arizona. Due to an error, Target was euthanized. (NYTimes story about Target is here.)
It's horrifying, of course, to imagine a beloved pet being euthanized accidentally. But I'm sorry, too, for the dog who was supposed to have been euthanized, the one whose death would not have made headlines.
During giving season, think about helping the ASPCA or your local shelters or rescue organizations so that they can save lives. If allowed to live long enough to be found and adopted, more dogs can have happier endings.