When I adopted both my cats from the Humane Society, they micro-chip and register them before you leave with them!! The younger was a kitten when we brought her home she was so little that you could not only feel the chip but see a bump under her fur. Not now, she has filled out and you would never know it. It is amazing the technology involved and how easily they are placed!!! I too have not had to use and am glad that they are protected!!!