Several years ago, a new dog came into the kennels who was an "iffy" dog. Most of the volunteers had experienced no problems with him, but several of the staff had. This was long before testing and behavior modification came to the forefront of shelter work.
While walking a couple who were potential adopters through, the gentleman saw this dog and exclaimed, "That's XXXXX. I know that dog. He bit me." He proceeded to pull up his shirt sleeve and show me the scar on his shoulder where the bite had happened.
I immediately excused myself, went and got our kennel manager to talk to the man, and sure enough, this dog had been turned into us clearly marked without a bite history. But upon further examination, this dog was listed on Sarasota County's dangerous dog list.
Now, I have no idea why he was turned into us. Most reasons are excuses anyway, but I am sure his owners didn't want the dog destroyed because he had bitten someone. So they lied.
The problem with this is, they are putting other members of society at risk. This dog had not bitten once, but several times. Ultimately, the dog was euthanized.
I wish this story was not the norm for daily intakes at shelters. But it is. People who don't want the animal anymore, will lie to assuage their guilt in turning the animal in. They see no problem in relinquishing a dog and hope you don't find out the truth.
Now incoming animals are checked for a bite history. If the incoming dogs have one, they are euthanized. Shelters and animal rescues cannot take a chance with human aggressive dogs. The risks are simply too high.