All vets, rescue shelters, and animal control officials have the ability to scan a cat if it's microchipped. The microchips are universally readable - it's like having a personal barcode on your kitty I highly recommend it. If someone finds your cat and takes them in, in all likelihood they will also be the kind of people who will notify authorities or take the cat to a vet if it's injured. All vets, rescue shelters, etc. normaly will scan a stray animal to see if it is microchipped.

Both of my cats are 'chipped. They are both indoor kitties too, but one never knows -- anything can happen. Living in earthquake country I'd rather be safe than sorry. HTH