I just wanted to restate.... every veterinarian whom offers micro-chipping services will scan a lost dog for a chip...consider it was a Yorkie found and Yorkie have  
collapsing trekia issues...he should have had a harness on...the likely hood of a collar..hmmmmm maybe there was a break away collar on him and it broke off...maybe his owner is elderly and couldn't get him as he got away or they are in the hospital, or maybe they are traveling in an RV...just waiting for animal control to respond their baby was found...no one will know if he isn't reported properly...as far as the legal issues...can you imagine if months later the owner sees someone with their dog who disappeared during a break in at their home and assumed the one who found their dog had been the one whom had broken into their home- 
It happened-same thing happened here when a car was stolen with a Yorkie-poo in it...right in front of the courthouse,...later the dog was recognized by a friend and the person whom had found the Yorkiepoo wondering had assumed stray not stolen...what a mess that was-they were technically in possession of stolen property and could have been in serious trouble for never having reported the dog found to animal control where she was listed missing...good thing the people were just so happy to get their dog back they didn't want any charges pressed..I'm searching for the article online but don't see it anywhere online. Here's an old missing post though from the local bulletin board.... 
STOLEN DOG (McKinleyville) | citytheft.com Myers Flat where the truck was found is over an hour away from Eureka and the owners live in McKinleyville another two towns over from Eureka...I believe Jack was found about 3 hours away from the Myers Flat area...