Is that a religious or superstitious thing? I don't think any shelters or pet stores in Australia do that ...

While I personally think it would be a bit silly to impose your religious or superstitious belief on others, I would agree to the policy if people tended to "adopt" black cats just for haloween. Or worse, if there were satanists who used them in rituals or something. And I would definitely be a bit suss about this lady!