If you don't delete it, here's the message you will receive when running cmapplyconf or cmcheckconf:
Checking nodes ... Done
Checking existing configuration ... Done
Warning: Unable to get configuration for cluster CLUSTER_NAME
Error: Node HOSTNAME is refusing Serviceguard communication.
Please make sure that the proper security access is configured on node
HOSTNAME through either file-based access (pre-A.11.16 version) or role-based
access (version A.11.16 or higher) and/or that the host name lookup
on node HOSTNAME resolves the IP address correctly.
cmcheckconf : Failed to gather configuration information