When I enquired with the event organisers for a CAMS/AASA event which I regularly attend, I was advised that their insurance provided covers me for "personal accident", including injury and damage to track facilities but not to my car or other cars.
At Driver Dynamics Sandown day their advice was that no cover of any sort was provided, whether it be injury or track facilities, cars.
So in conclusion, best to check with each event in advance as I have not found a standardised rule to this.
