Yes, I've always been concerned that a rescue might find an endangered or threatened species in their hands, or some other species with a very small captive gene pool that won't be added to again...it would be a shame to remove the option to breed such an animal simply because its previous owner had to surrender it suddenly.

I do think MOST rescues are more concerned with doing the right thing, whatever that might be in the circumstance. And certainly there is no cause to breed green iguanas.