Hello Peter,
I don't think any of standard Symantec documents on idea to start a single node cluster.
the VCS startup scripts does a check inside to see if GAB is only configured for one node, If condition comes true, it triggers a "hastart -onenode" which will start had.
You can modify this script to workaround the scenario.
Why Symantec didn't documented, well... Single node cluster is not actually a cluster (just presuming) & hence out of recommendation by Symantec..... :)
Cheers
Gaurav