Installing on GKE Autopilot Private Cluster

[raghu-manne]

I am installing sealed secrets on GKE Autopilot Private Cluster; i am installing the controller on the different namespace than the kube-system. Controller seems working fine and able to unseal and create k8s secrets.

But my concern is, here it is mentioned some firewall rules needs to be created to get it working. I have tested without creating firewalls and the controller is working as expected.
Is there something that would break if i don't create firewall rules?