This is a classic case of an EC that’s too lazy to check their own by-laws and make sure they reflect what their community wants.
The default model by-law says, as has been discussed, that you can’t have a pet without permission and permission can’t be unreasonably refused.
As we have pointed out many times in Flat Chat, saying that you have never allowed pets is not “reasonable” grounds for refusal becasue the by-law still allows pets, albeit under certain conditions.
In this instance, I suspect Claire has a pretty strong case to take to Fair Trading and NCAT (especially since the EC has refused to mediate). But this is an object lesson for Owners Corps that really don’t want pets in their buildings. Your by-laws have to reflect that and if you don’t have the support to change the by-law, then maybe the EC is out of step with its owners.