From what I've heard, microchipping does not locate them. It isn't like a GPS tracker. But I guess there is a part that can be scanned by a vet or someone with a scanner. So, if your pup was taken in as a lost dog they could scan her to see if the owners information pops up. Therefore, someone has to be proactive in taking your pup into the right place.   
I've heard (and please correct me if I'm wrong) that there are different types of microchips and not all vets have the same scanner. So the person scanning your pup would need to have the right scanner for the type of chip that you have in your pup.   
I go back and forth on this issue too.     
				__________________   Kona    Bernie        |