Our take on insurance (This piece was knicked from a Nurburgring forum), but we at Nurburgringers.net think its spot on.
 We can not be held responable for anything written here.
  Fully Comp protection for own vehicle: They can exclude FC with pretty much whatever terms they like. Its normal to exclude some aspects of cover such as theft in certain areas / countries especially the east eg Poland but also sometimes Italy. Most policies also limit your FC on the continent to a limited number of days per year. If you don't like it buy your insurance elsewhere.
  3rd Party: Seems widely misunderstood. The reciprocal 3rd party cover rules do oblige them to pay out but this is designed to protect the 3rd party, NOT YOU. Basically this means the 3rd party can claim against your insurance and they must pay, but they may then come after you to recover the costs as you were not covered !
  Someone correct me if I'm wrong, but I believe that if you hit the barriers the Nurburgring GmbH will insist on either you pay on the spot (usually credit card), OR, provide valid insurance details so they can claim from your 3rd party insurance. If 3rd party payout was hit & miss I'm sure they wouldn't accept this method so I guess they are always successful in forcing a payout if you go the insurance route.
  However, we've seen the insurance co refuse to reimburse 3rd party (barrier) costs paid by credit card on the basis that cover was invalid on the Nurburgring so while the GmbH can make them pay the same is not necessarly true for you.

Exclusion clauses:
  So far I've heard stories of people being payed out fully comp even when their policy has one of the specific exclusions (eg Nurburgring by name or "derestricted toll road etc"), plus the 3rd party aspect of barriers etc paid also.
  I've also heard examples of the insurance co refusing to pay even though there was no specific exclusion worded around the ring. In one case they used the generic "race track" clause to deny cover despite it being TF, non competitive, untimed etc because they argued it is clearly also a track. This case was taken to the insurance ombudsman who sided with the insuance co and the driver was not reimbursed for their car OR for the 3rd party damage to barriers (paid by credit card).
  Some may point to Monaco or other street circuits and say they are the same, but in normal traffic on those you are unlikely to be denied payout for a legit RTA, and if they did the obudsman would probably side with you as its normal driving.
  So we have both extremes, and its clear that it really just comes down to how "on the ball" the insurance company are when processing the claim.