Thinking back, I would have passed on the insurance, honestly.
One of my group asked the instructor if anyone had wrecked a car and needed to use the insurance. He said one guy was driving overly aggressive in the figure eight session and swiped the barrels. Ford Racing fixed that damage and didn't ping the guy (who had insurance). They basically hinted that the insurance was not necessary.
Just don't intentionally ram any barriers/buildings and you'll be fine.