You don't have to have insurance. When I attended last week I was the only person who I spoke to that had bought insurance (yes I talk to myself a lot). I didn't insure the full amount. Insurance companies allow you to inure the amount you feel happy with and you would only loose out if you wrote it off, as they would only pay out up to the amount you insured for. Any accidents that occur are always treated on a knock for knock basis on the track and will not effect your no claims bonus.
Anyone with Classicline insurance is covered for track days but you have to inform them a few days before hand.
To be honest everybody on the track behaved themselves and it was a good day. It was a little dawnting to start with but after the sighting laps behind the safety car I relaxed and had a good day, steadily increasing my speed throughout the event.
