Get the cat chipped!! It's super cheap, and it got me my spaniels back! Even if he's indoor only!
I let my dogs out, they are old school, they always come back. However one day a random kid "thought" they were lost and he took them home. Of course his MOM fell in love with the dogs! But his dad had the sense to get them scanned! He said, "If they didn't have a chip, my wife was not going to put any effort into finding the owner, she wanted those dogs!".