Did this owner do everything she could to protect her cat, such as putting up a fence to keep out the neighbor's dog?
Doesn't matter. It's the dog owner's resposibility to ensure that his dangerous animal (yes, dogs are dangerous, they KILL PEOPLE) was restrained in a manner to make sure that the animal did not escape and harm other people and property.
To say otherwise is to say that if some fool shoots his gun into the air on Cinco De Mayo and the bullet comes back down and hits you in your car, he is not liable if you didn't have your seatbelt on since you didn't do everything you could to protect yourself from possible injury. Or that the burglar who broke into your house is not liable since you chose to have glass windows that allowed him to enter - obviously, you didn't do everything you could to protect your house, so he shouldn't be liable, right?