The local animal control shelter asked me to foster a little rat terrier. Sad story, she got hit by a car, somebody dumped her at a vet's office, he thought she had a broken pelvis. He scanned her, found a microchip and called the owners, they wouldn't claim her because they were afraid of a big vet bill. Vet didn't want her, of course, so he called animal control. They picked her up and their vet x-rayed her and found nothing broken, she was just bruised. She was walking again the next day. They called me and asked me to foster her until her scrapes and bruises healed and they could find her a permanent home. They knew exactly what they were doing, I adopted her three days later.
I'd like to think the former owners were in desperate financial straits, to give her up. I would sell all my bikes, my boat, my car, and my furniture if I had to, to pay for her health care. Their loss is my gain, she is just a delightful little thing.