I want to further add that in most cases, the laws such as the CA law cited are unenforceable. If I took in a stray and took it to the vet, and it was living in my house, how can the neglectful owner prove it isn't my cat? I have vet bills to prove it's my cat. It's highly unlikely the cat would have been micro chipped, but even so, a vet could put a new one in for me. I doubt any neglectful or abusive pet owner would press the point legally. If so, I would counter by filing charges against him or her for animal neglect. There are some laws that are too unjust to be followed.