A VLA event will have the minimum liability insurance requirement stated on the Notice of Race. This insurance would cover death or injury to another person, or damage to someone else's boat, among other things.
This type of insurance is available from numerous insurance companies and is usually built into boat insurance (damage or loss) cover, or can be purchased by itself. This cover is usually a minimum requirement to compete in most other sailing and sporting events these days.
The insurance provided by the Yachting Australia Silver Card and Youth Card (via your sailing club membership) is for personal accident insurance only.
Some insurance company examples on the Links