A Holden VE Alternator is known to fail and can vary in when. My Dad had one fail around the 120,000kms in his VE SS but I never had an issue in my VE Omega and it did over 200,000kms.
When you get the warning, it is always best to check the battery voltage to see if it is still functioning. Even if it is, it could be intermittent which is why the warning light has been triggered. If you have access to an OBD2 Tool, it might be worth giving the ECU a scan.
Overall, it is recommended to try and get the Alternator replaced to avoid you being stranded. It can cause other computer issues due to low voltage in the battery which might trigger the check engine light or other fault lights.