I worked for a vet and can tell you firsthand that one reason a vet doesn't always report to the SPCA, is because they know it may be a death sentence for the animal. Same goes for individuals who contact rescue groups instead of the SPCA. To report a neglected animal, only to have it killed instead of vetted and rehabbed, leaves the complainant with terrible guilt. Better to take matters into their own hands and leave the SPCA out of the picture. If it's going to be mandatory to report cases to the SPCA, then I think it should be mandatory that the SPCA help the animal, and not kill it.