Its a very sad situation. it really leaves no time for even an owner to find their pet. I have a friend that lost her Weimaraner. She called all the shelters in the area. She decided (thankfully) to go to the main shelters. She found her dog at the first one she called and went to. They said on the phone that there are no Weimaraners there. None had been picked up or dropped off. I was horrified. If she had not gone and looked for herself who knows what would have happened. I guess another lesson we learn. Never take the word of them either. Always go look for yourself.
you always have to go in person. The shelter workers (especially in high kill facilities) don't see all the intakes, many lack staffing etc. And not all can identify breeds. Chips are still good. People who find dogs and are aware of chips may take them to a shelter or vet to be scanned. Also, many shelters do scan. Especially the ones working towards no-kill. It's best to call your area shelters and rescues and ask. My dog is chipped and I know the kill shelter scans on intake and before euth. It's still not 100% because of human error, but . . . I have the tag from the no-kill shelter I got her at on her collar along with my tag. I also know most (if not all) rescues here scan and if the kill shelter didn't scan, they would let you know

The no-kill shelter by me got a call from a shelter in CA. They had one of their dogs. They scanned before euth as a double check. Dog got flown back to Brooklyn and placed in a new home. I have pictures of the pup on one of my drives. Oh, and if the scanner can't read a chip, it can detect one. We've run into that, but most scanners are universal for the most common frequency. I think it's Banfield that was putting out the Euro frequency chip, but they double chip now. We had a chip we couldn't read and they took the dog to a vet that had the scanner up the street. But this was a good 6 yrs ago and I know things are more universal now. Home Again and Avid are the 2 most popular and those are the ones I would stick with. Check with what most of the shelters and rescues in your area are chipping with. Here, it's Home Again.