I do not approve of micro-chips on principle. I know that others have found this form of tracking to be beneficial, but it is not absolutely necessary.
Our family has owned well over 30 dogs in our lifetime, not including livestock, and our pet cats. Our felines were never in a situation involving their collars being snagged on fences, etc. Although, I will say that the cats we currently own have no collars. We live out in the wild; in an isolated location, so there is no risk of being run over, but they could be caught on brush or in a tree, so they don’t wear the collars.
It has been a rare occasion when one of our dogs ran away. As a matter of fact, I can only recall two occasions. Once, when we had just arrived home from the animal shelter w/our dog. He slipped through the rope and ran off. We managed to call him back shortly thereafter.
The other occasion occurred during a hunt. After waiting well after nightfall, then going home, we returned the next day to find our dog waiting on the t-shirt we left for him.
People have managed to take care of their pets w/out the devices, but it is a personal choice that provides owners with that added sense of security. I would venture to say that the micro-chip may even cause the owner to be neglectful knowing that if his/her pet should run off, they’ll be easily found.
I see neglectful owners all the time. They don’t bother putting their dogs on leashes or securing the kennel, the dogs runners, or fenced yard. We’ve never had that problem.
If you look at my profile page, you'll see my old Shepherd Timber. I got him at about 7 weeks and he never left my side. Even though he was not neutered, and even when a bitch in heat would prowl through the neighborhood, he wouldn't stray off (although he'd salivate pretty heavily ;-). We bonded at a very early age and he was well disciplined. Although I didn't need it, I had a fenced yard for him. He was never chipped, and a chip was never needed.
You'll also see pics of my Tervuren, Ranger. He was rescued after Katrina at an estimated 18 months. He was intact at the time, but the policy of the rescue society I was working with at the time was to neuter/spay before adoption so he got snipped at about a year and a half. God only knows how he survived in the weeks following the storm prior to his rescue but he's very cat and squirrel aggressive. During the first year I had him, he went both over and under a 7' privacy fence. On one occasion, he was in the car and saw a cat I had not seen. No sooner had I cracked the door open than he was over me and out the door...Reluctantly I had him chipped and over the next year of so, there was one occasion when it paid off, and in the interim his desire to free range has been greatly curbed and tempered; nevertheless, having him chipped probably spared him from some possibly sad fate.
I would hardly consider myself a careless or negligent dog owner, and under ideal circumstances would not have any dog chipped. Having said that, I believe there are some circumstances where I do believe it's a lesser evil sort of choice.
I would also add to my #85 that in some circumstances where a dog becomes separated fro it’s owner and a dispute arises over ownership or identity like happened here in Louisiana after Katrina, or virtually anywhere dogs are “dog-napped”, a thief or would-be owner can easily remove a tag and lose placing the dog’s ownership in question. A chip...not so easy, and certainly a means of very positive identification.