On a rare vet visit for rabies shot this spring, I had the vet verify the chips. Gwynnie's gave no signal! She'd been running around as long as 7 years with a defective or missing microchip. Home Again replaced it free of charge. It may have fallen out. We'd seen this happen before.
I was reminded by the story of the corgi returned after 11 years via the microchip.
This crossed my mind. So anybody, if you're ever scanning a dog for a chip, be very thorough and go over the entire animal.
Gwynie's 1st chip did fall out, Lori chanced to notice it while combing her.
Many people are probably relying on chips that are unreliable.