Notwithstanding legal technicalities about pets which were adopted out on a permanent basis, there's a special place in hell for anyone who adopted a pet whose hurricane-victim owner later located the pet, and then refused to give the pet back on the grounds that "it's legally mine now" -- and there have been a few reports of this.
There will always be reports of people acting selfishly and even wrongly... That's what people do. I just don't blame the volunteers who worked hard to collect and then find homes for, the many abandoned and lost animals.