From the Houston Chronicle:

The thin, brown and white pit bull puppy in cage 64 was seconds away from becoming a sad statistic, one of thousands of animals euthanized at Houston's animal shelter last year.

Animal control officers found him wandering the streets — sans tags — on the northwest side of Houston. When they got to the shelter at 3200 Carr, they scanned his lean body for a microchip, but found nothing.

Then, a few days later, just before he was scheduled to be euthanized, kennel workers scanned the dog again. This time, they got a hit that saved the puppy's life.

Because chips can migrate within an animal's body, shelter policy requires workers to scan each animal twice — once at intake and a second time before it is adopted or euthanized.

You can read the rest of the Chronicle article here.

All clinics/rescue/pet organizations should be required to scan pets that are brought in.

I also wish that "we", i.e., pet owners would push to require Vets to scan all new pets brought to their facility. As of now, they only scan when it is disclosed the animal was found.

There is no reason this is not a matter of practice. The scanners are cheap and it only takes a few seconds.